diff --git a/lib/Cron/CronWorkerRunner.php b/lib/Cron/CronWorkerRunner.php
index 0ee10f7b94..262f75fd46 100644
--- a/lib/Cron/CronWorkerRunner.php
+++ b/lib/Cron/CronWorkerRunner.php
@@ -3,6 +3,7 @@
 namespace MailPoet\Cron;
 
 use MailPoet\Models\ScheduledTask;
+use MailPoet\Newsletter\Sending\ScheduledTasksRepository;
 use MailPoet\WP\Functions as WPFunctions;
 use MailPoetVendor\Carbon\Carbon;
 
@@ -23,15 +24,20 @@ class CronWorkerRunner {
   /** @var WPFunctions */
   private $wp;
 
+  /** @var ScheduledTasksRepository */
+  private $scheduledTasksRepository;
+
   public function __construct(
     CronHelper $cronHelper,
     CronWorkerScheduler $cronWorkerScheduler,
-    WPFunctions $wp
+    WPFunctions $wp,
+    ScheduledTasksRepository $scheduledTasksRepository
   ) {
     $this->timer = microtime(true);
     $this->cronHelper = $cronHelper;
     $this->cronWorkerScheduler = $cronWorkerScheduler;
     $this->wp = $wp;
+    $this->scheduledTasksRepository = $scheduledTasksRepository;
   }
 
   public function run(CronWorkerInterface $worker) {
@@ -42,7 +48,8 @@ class CronWorkerRunner {
 
     if (!$worker->checkProcessingRequirements()) {
       foreach (array_merge($dueTasks, $runningTasks) as $task) {
-        $task->delete();
+        $this->scheduledTasksRepository->remove($task);
+        $this->scheduledTasksRepository->flush();
       }
       return false;
     }
@@ -75,11 +82,11 @@ class CronWorkerRunner {
   }
 
   private function getDueTasks(CronWorkerInterface $worker) {
-    return ScheduledTask::findDueByType($worker->getTaskType(), self::TASK_BATCH_SIZE);
+    return $this->scheduledTasksRepository->findDueByType($worker->getTaskType(), self::TASK_BATCH_SIZE);
   }
 
   private function getRunningTasks(CronWorkerInterface $worker) {
-    return ScheduledTask::findRunningByType($worker->getTaskType(), self::TASK_BATCH_SIZE);
+    return $this->scheduledTasksRepository->findRunningByType($worker->getTaskType(), self::TASK_BATCH_SIZE);
   }
 
   private function prepareTask(CronWorkerInterface $worker, ScheduledTask $task) {
diff --git a/lib/DI/ContainerConfigurator.php b/lib/DI/ContainerConfigurator.php
index 11e75e13a3..651f23e5da 100644
--- a/lib/DI/ContainerConfigurator.php
+++ b/lib/DI/ContainerConfigurator.php
@@ -360,7 +360,7 @@ class ContainerConfigurator implements IContainerConfigurator {
     $container->autowire(\MailPoet\Newsletter\Statistics\NewsletterStatisticsRepository::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\Scheduler\WelcomeScheduler::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\Scheduler\PostNotificationScheduler::class)->setPublic(true);
-    $container->autowire(\MailPoet\Newsletter\Sending\ScheduledTasksRepository::class);
+    $container->autowire(\MailPoet\Newsletter\Sending\ScheduledTasksRepository::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\Sending\ScheduledTaskSubscribersRepository::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\Sending\SendingQueuesRepository::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\ViewInBrowser\ViewInBrowserController::class)->setPublic(true);
diff --git a/lib/Models/ScheduledTask.php b/lib/Models/ScheduledTask.php
index 8ec936cabf..aec9d454f1 100644
--- a/lib/Models/ScheduledTask.php
+++ b/lib/Models/ScheduledTask.php
@@ -164,14 +164,6 @@ class ScheduledTask extends Model {
       ->findOne() ?: null;
   }
 
-  public static function findDueByType($type, $limit = null) {
-    return self::findByTypeAndStatus($type, ScheduledTask::STATUS_SCHEDULED, $limit);
-  }
-
-  public static function findRunningByType($type, $limit = null) {
-    return self::findByTypeAndStatus($type, null, $limit);
-  }
-
   public static function findFutureScheduledByType($type, $limit = null) {
     return self::findByTypeAndStatus($type, ScheduledTask::STATUS_SCHEDULED, $limit, true);
   }
diff --git a/lib/Newsletter/Sending/ScheduledTasksRepository.php b/lib/Newsletter/Sending/ScheduledTasksRepository.php
index 9f313b7635..025535ea1e 100644
--- a/lib/Newsletter/Sending/ScheduledTasksRepository.php
+++ b/lib/Newsletter/Sending/ScheduledTasksRepository.php
@@ -7,6 +7,8 @@ use MailPoet\Entities\NewsletterEntity;
 use MailPoet\Entities\ScheduledTaskEntity;
 use MailPoet\Entities\ScheduledTaskSubscriberEntity;
 use MailPoet\Entities\SendingQueueEntity;
+use MailPoet\WP\Functions as WPFunctions;
+use MailPoetVendor\Carbon\Carbon;
 use MailPoetVendor\Doctrine\ORM\Query\Expr\Join;
 
 /**
@@ -87,6 +89,45 @@ class ScheduledTasksRepository extends Repository {
       ->getOneOrNullResult();
   }
 
+  public function findDueByType($type, $limit = null) {
+    return $this->findByTypeAndStatus($type, ScheduledTaskEntity::STATUS_SCHEDULED, $limit);
+  }
+
+  public function findRunningByType($type, $limit = null) {
+    return $this->findByTypeAndStatus($type, null, $limit);
+  }
+
+  protected function findByTypeAndStatus($type, $status, $limit = null, $future = false) {
+    $queryBuilder = $this->doctrineRepository->createQueryBuilder('st')
+      ->select('st')
+      ->where('st.type = :type')
+      ->setParameter('type', $type)
+      ->andWhere('st.deletedAt IS NULL');
+
+    if (is_null($status)) {
+      $queryBuilder->andWhere('st.status IS NULL');
+    } else {
+      $queryBuilder
+        ->andWhere('st.status = :status')
+        ->setParameter('status', $status);
+    }
+
+    if ($future) {
+      $queryBuilder->andWhere('st.scheduledAt >= :now');
+    } else {
+      $queryBuilder->andWhere('st.scheduledAt <= :now');
+    }
+
+    $now = Carbon::createFromTimestamp(WPFunctions::get()->currentTime('timestamp'));
+    $queryBuilder->setParameter('now', $now);
+
+    if ($limit) {
+      $queryBuilder->setMaxResults($limit);
+    }
+
+    return $queryBuilder->getQuery()->getResult();
+  }
+
   protected function getEntityClassName() {
     return ScheduledTaskEntity::class;
   }
diff --git a/tests/integration/Models/ScheduledTaskTest.php b/tests/integration/Models/ScheduledTaskTest.php
index e241a10a04..614ba7cb6f 100644
--- a/tests/integration/Models/ScheduledTaskTest.php
+++ b/tests/integration/Models/ScheduledTaskTest.php
@@ -181,74 +181,6 @@ class ScheduledTaskTest extends \MailPoetTest {
     expect($timeout)->equals(ScheduledTask::MAX_RESCHEDULE_TIMEOUT);
   }
 
-  public function testItCanGetDueTasks() {
-    // due (scheduled in past)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => ScheduledTask::STATUS_SCHEDULED,
-      'scheduled_at' => Carbon::now()->subDay(),
-    ]);
-
-    // deleted (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => ScheduledTask::STATUS_SCHEDULED,
-      'scheduled_at' => Carbon::now()->subDay(),
-      'deleted_at' => Carbon::now(),
-    ]);
-
-    // scheduled in future (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => ScheduledTask::STATUS_SCHEDULED,
-      'scheduled_at' => Carbon::now()->addDay(),
-    ]);
-
-    // wrong status (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => null,
-      'scheduled_at' => Carbon::now()->subDay(),
-    ]);
-
-    $tasks = ScheduledTask::findDueByType('test', 10);
-    expect($tasks)->count(1);
-  }
-
-  public function testItCanGetRunningTasks() {
-    // running (scheduled in past)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => null,
-      'scheduled_at' => Carbon::now()->subDay(),
-    ]);
-
-    // deleted (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => null,
-      'scheduled_at' => Carbon::now()->subDay(),
-      'deleted_at' => Carbon::now(),
-    ]);
-
-    // scheduled in future (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => null,
-      'scheduled_at' => Carbon::now()->addDay(),
-    ]);
-
-    // wrong status (should not be fetched)
-    ScheduledTask::createOrUpdate([
-      'type' => 'test',
-      'status' => ScheduledTask::STATUS_COMPLETED,
-      'scheduled_at' => Carbon::now()->subDay(),
-    ]);
-
-    $tasks = ScheduledTask::findRunningByType('test', 10);
-    expect($tasks)->count(1);
-  }
-
   public function testItCanGetCompletedTasks() {
     // completed (scheduled in past)
     ScheduledTask::createOrUpdate([
diff --git a/tests/integration/Newsletter/Sending/ScheduledTasksRepositoryTest.php b/tests/integration/Newsletter/Sending/ScheduledTasksRepositoryTest.php
new file mode 100644
index 0000000000..044475b76b
--- /dev/null
+++ b/tests/integration/Newsletter/Sending/ScheduledTasksRepositoryTest.php
@@ -0,0 +1,60 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Newsletter\Sending;
+
+use MailPoet\Entities\ScheduledTaskEntity;
+use MailPoetVendor\Carbon\Carbon;
+
+class ScheduledTasksRepositoryTest extends \MailPoetTest {
+  /** @var ScheduledTasksRepository */
+  private $repository;
+
+  public function _before() {
+    parent::_before();
+    $this->cleanup();
+    $this->repository = $this->diContainer->get(ScheduledTasksRepository::class);
+  }
+
+  public function testItCanGetDueTasks() {
+    $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_SCHEDULED, Carbon::now()->subDay(), Carbon::now()); // deleted (should not be fetched)
+    $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_SCHEDULED, Carbon::now()->addDay()); // scheduled in future (should not be fetched)
+    $this->createScheduledTask('test', '', Carbon::now()->subDay()); // wrong status (should not be fetched)
+    $expectedResult[] = $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_SCHEDULED, Carbon::now()->subDay()); // due (scheduled in past)
+    $expectedResult[] = $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_SCHEDULED, Carbon::now()->subDay()); // due (scheduled in past)
+    $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_SCHEDULED, Carbon::now()->subDay()); // due (scheduled in past)
+
+    $tasks = $this->repository->findDueByType('test', 2);
+    $this->assertCount(2, $tasks);
+    $this->assertSame($expectedResult, $tasks);
+  }
+
+  public function testItCanGetRunningTasks() {
+    $expectedResult[] = $this->createScheduledTask('test', null, Carbon::now()->subDay()); // running (scheduled in past)
+    $this->createScheduledTask('test', null, Carbon::now()->subDay(), Carbon::now()); // deleted (should not be fetched)
+    $this->createScheduledTask('test', null, Carbon::now()->addDay()); // scheduled in future (should not be fetched)
+    $this->createScheduledTask('test', ScheduledTaskEntity::STATUS_COMPLETED, Carbon::now()->subDay()); // wrong status (should not be fetched)
+
+    $tasks = $this->repository->findRunningByType('test', 10);
+    $this->assertSame($expectedResult, $tasks);
+  }
+
+  public function cleanup() {
+    $this->truncateEntity(ScheduledTaskEntity::class);
+  }
+
+  private function createScheduledTask(string $type, ?string $status, \DateTimeInterface $scheduledAt, \DateTimeInterface $deletedAt = null) {
+    $task = new ScheduledTaskEntity();
+    $task->setType($type);
+    $task->setStatus($status);
+    $task->setScheduledAt($scheduledAt);
+
+    if ($deletedAt) {
+      $task->setDeletedAt($deletedAt);
+    }
+
+    $this->entityManager->persist($task);
+    $this->entityManager->flush();
+
+    return $task;
+  }
+}