I’m not really a locksmith, but when you need to get a key for an old trunk lock and you can’t find another one the same on the internet, you either buy the closest match (which I couldn’t find) or make one yourself.
I took an old 5 bar house key, took the lock apart and started filing the key down to fit the lock, I also had to drill down the centre of the key shank for it to fit over the lock guide pin.