With Scheduled Issue Statistics option you can easy check how many Schedule Issues and Subtask are created in every project on your Jira instance.
To check it you need to as Jira Administrator go to the Jira Settings (1) → Apps (2) → Scheduled Issue Statistics in the The Scheduler section (3).
After click on the number of existing scheduled issues, you will be redirected to the Scheduled Issues table in chosen project.
Additionally you can efficiently filter your projects to find chosen one (4).
Moreover at Created By The Scheduler column you can find information about number of created tasks by The Scheduler at project. By clicking it (5) you will be redirected to issue list with those created issues