I'm sensing a late 70's early 80's LTD.

One is the valet key. It should only work to turn on the engine and open the door.

The other key should work for the trunk, the glove box, the door, and to start the car.

you see how the pin layout is similar? There actually two sets of pins to allow different keys to work on one lock. That's how the school janitor's master key works for all the doors.

Edit: My mistake. All my info is wrong. Please ignore. Leaving it here so others can learn from my mistake or so people don't wonder what got deleted.

This was common for a long time. I have no idea why.

I barely even remember using physical keys to open my family's cars. Remote entry FOBs quickly became a thing when I was a kid.

If you make a mistake you can either ignite the trunk or trunk the ignition.

still have keys saved for some reason. cars are all long gone.

Trunk, but also the doors

Just like my wife.

70s, had Mavericks, Escorts, LTDs. all had keys like that. slowly replaced them over the years with electric door locks/windows, fobs