This is the model of the Key that I used in my Prototype Game Adventurous for the Oculus Quest: http://brainslugs83.itch.io/adventurous
Also it's available in my open source UnityCommon package in the Models folder: https://github.com/BrainSlugs83/UnityCommon
If you use it in a project, leave a comment and let me know so I can check it out!
FYI, there's also a matching lock for it here: https://www.cgtrader.com/free-3d-models/various/various-models/low-poly-lock