FIRST give WD40 a try with its nozzle tube inside locks, after 5 minutes problem will be solved. Key masters are ready to rip you off.
its just because of petrified grease inside the lock due to not using them often. We use alarm remotes to open close, We troubled ourselves with this situation one day when all of sudden remote battery death.
We then in panic ready to spend on keys and locks, While real problem is those tinny locks bits inside lock get stuck in petrified grease due to not using them regularly.
140 Rs small WD-40 can solve this matter in 5 minutes only, after that you must use lithium grease for locks in spray packing. Lithium grease in spray bottle is hard to find from normal shops. Go for sewing machine lubricant instead.
Simple solution is this.