Update! Applying Vice-grips to the key I pulled the key put of the lock. But the lock is still in the "non-operating" position of 3 o'clock instead of 6 o'clock. Right now the lock is soaking in Kroil. Best penetrating oil and lube there is.
On this car the key cylinder is well-protected by metal and buried. Probably need a special tool to unscrew the cylinder and/or drill out a rivet under the lock and get to it through a tiny access panel.
Worst case it goes to the shop in the morning and they put a new cylinder in for me.
I may give the flat-bladed screwdriver a shot to turn the cylinder back to 6 o'clock.
ETA: I am honored that you all think I would have a dead hooker to transport, but unfortunately my life is too boring to deal with live or dead hookers. And it's my wife's car anyway, and I will not be getting pie or a threesome if I fix it today.
ETA: Gave up for the night. Suspect I need a new cylinder, and I won't have time during the week to attempt a do-it-yourself job. For now the trunk is duct-taped shut, ghetto-style.