you can get one either from the raid right path(path 1), be lucky at some chests or boxes(not sure if they drop anymore but I heard that steel and premium chests do), or by buying from market.
key two can be found in a premium chest if really lucky. Keep watching the market as someone might find one in a chest and put it on the market. Expect to pay at least 350k for it. Key three can be found in steel lined chest.