This keychain wasn't made to be babied. It was made to be used. It'll get marked, it'll darken where you hold it, it'll develop a patina that's yours alone.
That's not wear. That's what real leather does.
If something spills on it, wipe it with a dry cloth and let it air dry — away from the sun. Avoid soap, ink, and alcohol. That's it. The rest takes care of itself.