If you have an intelligent key instead, you can make a set of new keys at the car representative of the brand. Of course, you will need the car's documents proving that you are its rightful owner and the spare key. However, to avoid this situation, a good solution for car keys replacement is to have a keychain with a GPS location. It will show you the location of the keys on your phone, so you will be able to locate them quickly using the application. And the investment is not expensive at all.