Toyota - Venza :: 2011 - Door Lock Won't Open By Key?

Just bought a great 2011 Venza with 75000 Texan highway miles. Now that the car is home, I've discovered that:

-- both of the remote fobs will lock and unlock the car doors,-- but neither of the two keys will lock or unlock the driver's door (the only one with a key slot, you know).

The key turns freely to right and left, with a slight, normal-feeling resistance. But nothing happens. No doors lock or unlock.

I've tried graphite in the key slot and working the key in and out. No luck.

So it seems 1) the keys are fine, as they start the car when put into the ignition.

And 2) the locks themselves also seem to be fine: both remotes lock and unlock the doors.

But 3) the driver's door can't be locked or unlocked using the key.

What worries me is that the car battery will die and I won't be able to unlock the car door in order to pop the hood open.