What does "key card" mean in English for Spanish?

In English for Spanish, "key card" means:

tarjeta llave

Listen to "key card": (If you have an HTML5 enabled browser, you can listen to the native audio below)

This is a phrase that is used in the GamesForLanguage English for Spanish Language Game in the following scenes:

• English for Spanish 4, Level 3, Scene 1
• English for Spanish 4, Level 3, Scene 2
• English for Spanish 4, Level 3, Scene 3