Okay, it isn’t so easy, but the following help you to the right track.

If you don’t have a separate service-account for Local AD connection, then you can use this:

dsquery user -name MSOL_AD_sync

If you have a service-account, replace MSOL_AD_sync with that one.

Answer: “CN=MSOL_AD_sync,CN=Users,DC=domain,DC=local”

Next type:  DC repadmin /showobjmeta <DCNAME> <DN of MSOL_AD_sync or the service-account>

See for LastLogon or UserAccountControl attributes, they will lead you the way.