In short

Keycard Art Gallery is a keycard for the building “Art Gallery” in Palm Side. It opens: vault. Behind the door: 2 large safes, 1 computer · Brick, Fragile Figurine, Cheap Antiques. The key fits only this place.

KeyBuildingDistrictOpens
Keycard Art GalleryArt GalleryPalm SideVault

Where it is

The building is on the interactive map. All keys, doors and safes of the city: Locked doors, Safes and containers, the key guide.

The game data does not list where this key drops or is sold, so we do not guess.