What if I have a activation lock one my old phone

Recycle it, or recover the Apple ID and password (https://iforgot.apple.com) or initiate account recovery if you were the original owner and can prove it→How to use account recovery when you can’t reset your Apple ID password - Apple Support

Until you can unlock it with the correct Apple ID & password that was used to lock it, it is useless to you.

No.

Recycle it responsibly.

Take it to any Apple store or Apple authorized service provider, or your municipal electronics recycling center if it has one.