add email event date index

db/migrate/20250530080846_add_email_events_date_index.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class AddEmailEventsDateIndex < ActiveRecord::Migration[8.0]
+  def change
+    remove_index :email_events, :account_id
+    add_index :email_events, %i[account_id event_datetime]
+  end
+end