If the manual/key locks have not been used in awhile, they may have road grime in them that inhibits the cylinder turning its full range. You might want to give the locks a squirt is silicone spray, let it penetrate and then gently work the locks to see if you can free them. This assumes, of course, that the key fits the exterior openings as well as the ignition.

Some forum members will advocate WD-40 on locks, but in time it evaporates to a gummy residue, which is not a good thing...

If the key isn't badly worn, it sounds like the ignition barrel has been replaced with a different key at some time. Tibbe locks are designed so any key can lock a door, but only the correct key will open it.

Unfortunately it does sound like time to call an automotive locksmith.