How can I tell if my 1973 VW Super Beetle has bad engine mounts?
Fired you? Punched you in the face? Touched you in a sexual way? Let's go with fired you, since it seems like that's where you were going. Generally speaking, most employees are at will. This means your boss can fire you for any non protected reason, without notice. Using a gym while your on duty would certainly be a justified reason for firing you. If you are a contract employee (not a contractor employee) then the terms of the contract would dictate when you can be fired. You need to give more information for a better answer.
Take the locks out and have a locksmith recode them to a different keymuch cheaper than buying a whole new set.