Jenny:
If you're looking to see when Salesforce has synced with Marketo, you can find this in Admin > Salesforce. In the top right corner it says "Last Synced: (date), (time)."
This means having Admin rights. The sync is also for when the Marketo side and Salesforce side have completed. So if you're running a job that is taking ten minutes, this sync probably won't encompass it until the job is complete.
I did the math once of when the sync happens. I think it's every 7 minutes.
Best,
Edward UnthankMarketing Operations Specialist
Yesler