Hello az1z_dobriy,
Thanks for choosing the Apple Support Communities. We understand your Mac is Activation Locked and you cannot remember the associated Apple ID. We can help.
You'd want to start by following these steps to attempt to retrieve your Apple ID:
If you forgot your Apple ID email address or phone number - Apple Support
Once retrieved, here is how to change your Apple ID password:
If you forgot your Apple ID password - Apple Support
If you're unable to retrieve your Apple ID, you would want to look at how to remove Activation Lock:
How to remove Activation Lock - Apple Support
We hope this helps.
Cheers!