I don't think that would be this quick either.
Since the code might/will mess up zeropage and/or other dataareas in use by the C64 basic, you would have to wipe it to a known state for each test, which almost means "boot up the KERNAL and let it run complete INIT".
Not that even this have to take a long while on a 3GHz computer running full speed, but doing it 2^272 times ...