Your first cuff is a cuff from Argentina. They were most likely made by Halcon.
The key isnt very complicated, if you try to make one yourself. Maybe find a similar that fits and use a hand file to modify it until it works? I used this key from an Fury Model 15900 High Security Handcuff. I had to thin the key a bit with a file and file the tip down a little, if memory serves me correctly?
The second cuff you have is a child's toy handcuff. It opens via the push button. There is no key for these and were never used as restraints. This seller lied to you, either by them not knowing exactly what they were, or them trying to make some money off of an unsuspecting buyer.
-Richard Knip-