You do not use it when you find it.
When you get free in the Black Widow's hideout, the key card will open the door to her collection of stolen treasures, where you battle her at the end of the game.
The key card opens the door to the Black Widow's art room, where you complete the game. (You need the key from the curator of the Museum to track her down.)
It opens the locked door to the Black Widow's gallery of stolen art. Use it when you need to get past her guards in the Widow's lair. (This is at the end of the game.)
When you find it, nothing. Later in the game, it opens a locked door in the Black Widow's lair.
It will.
you get in the boat and sink
The key card is for later. Return to the museum, where you have a package waiting for you.
if you want keycard then go to poptropicahelp.net and do island guide
There is nothing to do with the key card immediately. Go back to the museum to find a package waiting for you. You will be leaving Counterfeit Island (temporarily) to travel to another island, for some valuable information.
its on the edge of the dock
When the strange man jumps in the boat he will drop it
The key card is used later in the game in the Black Widow's lair. Save the key card and return to the museum.
The key card is dropped at the end of the scooter chase. It is used much later in the game.
When he leaves he will leave it on the docks
a girl named paisley
The Black Widow key card is dropped by the art thief (shady guy) when he makes his escape by boat.