The MR2 came with a master and a valet key. The master key operates all locks. The valet key only operates turns the engine on/off. It does not function on the glove compartment or the trunk. (The trunk lock can be disengaged from the in-cabin trunk release to prevent someone in the car from opening the trunk.)
In order to get a new master key, take your VIN to a Toyota dealer and they will be able to get you a new master key. You will probably need some kind of proof that you own the car.