Activation lock

If you're not the original owner and you cannot contact the original owner, you're out of luck

Recycle the iPhone and count it as an bad experience

See this link for further reference

The All Too Common SAD Reality of Buying … - Apple Community

If you are not the owner and do not have the Apple ID and Password then there is no way that you can get into this iPhone unless the original owner shares the Apple ID and password with you. If you are lucky you can get into this iPhone if they (owner) accidentally remove the device from their Apple ID.