instead of doing a keyed switch, what i would do is the following or some combination there of:
install this in the activation wire to the relay, such that your switch takes minimal current.
option 1 install magnetic switch somewhere on the dash with piece of steel surrounding it.
get magnet made with picture of you and lady friend on it. When you want truck to start magnet must be over switch to start. don't want truck to start then throw magnet in glove box. in case of emergencies run into vatozone/hd/oreillys and buy anything with a magnet.
option 2 acquire ignition cylinder or door cylinder keyed same as your vehicle, modify such that key can be removed in 2 positions. position 1 wired such that relay activates, position 2 wired such that relay doesnt activate.
option 3 combine option 1 and 2, use magnetic switch as primary and keyed switch in case of magnetic switch failure
option X would be to use a NFC receiver on your center console that requires your phone to be in place for the vehicle to start.
Lastly, good luck trying to flatbed a truck that's laying frame without attracting a whole lot of attention.