The VATS system that is the security chip in the key keeps the starter from even cranking and turns off the fuel injectors to help make difficult stealing the automobile.
VATS does not lock the motor physically.
One possibility might be hydrolock, where coolant has leaked into the cylinder and stopped the piston from coming up. Remove the spark plugs and try turning the motor. Even if hydrolocked the motor should have turned backwards. Trying to keep cranking the motor if it's hydrolocked will damage rods, pistons, and starters from the strain. Batteries too.
Other than hydrolock as problem, the engine now needs to be checked to find out what's not letting it turn.