diff --git a/app/models/solid_queue/process/prunable.rb b/app/models/solid_queue/process/prunable.rb
index ee63390a..c4f95729 100644
--- a/app/models/solid_queue/process/prunable.rb
+++ b/app/models/solid_queue/process/prunable.rb
@@ -4,7 +4,7 @@ module SolidQueue::Process::Prunable
   extend ActiveSupport::Concern
 
   included do
-    scope :prunable, -> { where("last_heartbeat_at <= ?", SolidQueue.process_alive_threshold.ago) }
+    scope :prunable, -> { where(last_heartbeat_at: ..SolidQueue.process_alive_threshold.ago) }
   end
 
   class_methods do