The Key lime (Citrus aurantifolia Swingle) presumably gets its name from the Florida Keys where it is commonly grown, having been introduced there some years ago. In comparison with the Persian lime, the Key lime is about half the size and more acidic. Its distinctive flavor makes Key Lime Pie popular in the US.
This knowlege helps make sense of the jellybean flavor pun used the NES adventure game, A Boy and His Blob. In that game, flavored jellybeans cause the blob to shapeshift into various objects to solve puzzles. In particular, the lime-flavored bean turns the blob into a key, an example of tasteful wordplay.