Mislaid phone with Lockscreen PIN active - is my data safe?

It looks as though I may have mislaid my Z3 Compact, running stock Android 5.0.2, never rooted. The SIM is secured with a 7-digit PIN, and I have the lockscreen enabled with a 7-digit PIN also. Encryption is not enabled, and remote locate and wipe was not set up.

I have texts and call recordings on the phone containing sensitive data. Should I consider the data on the phone compromised, or will the lockscreen PIN keep it contained?

Assume average Joe, not an Android pro.

Thanks guys.