How do you protect yourself from a keylogger?

mikhailkotsarenko If that should happen, all your credentials are compromised. In this case, you need to first get the invader out of your computer environment and make sure he is actually out, then change all your credentials. And all this faster than the criminal is able to use them. If you happen to store other personal information that cannot be changed to lock someone out, the damage is irreparable.
This is not 1password specific, this could happen with every compromised password manager database+master password.

To keep the risk as low as possible, apply best practice to keep your computer free of malware. Best practice includes (but is not limited to) keep your system and virus scanner updated and patched with the latest OS patches and be sure to install only trustworthy software from trusted sources only. It might be difficult to identify software or a source as trustworthy - if in doubt, ask a person more educated with computer use before proceeding.

Nobody is safe against zero day vulnerabilities, but chances are good you personally are not affected, because the time window between a zero day vulnerability gets abused widespread and your virus scanner signature or vulnerable app being updated to fix that security leak is somewhat small. So only very few people become victim in that short time span, and the probability you're included is not very high.