Go back to the museum. You have a package waiting.
The key card is for later. Return to the museum, where you have a package waiting for you.
After you chase the guy with the scar, you will see that he dropped his key card. Pick it up. This is on Counterfeit Island.
It will.
you get in the boat and sink
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.
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