To a limited extent, yes: the "navigate" event is fired at cards when cursor keys are released while in Interact mode. The handler is provided with one of the strings "up", "down", "left", or "right" as an argument. You can also produce these events with swipes by turning on "Nav Gestures" from the Decker menu.
If you don't supply your own, Decker provides a default "on navigate" handler which maps the left and right cursor keys to go["Prev"] and go["Next"], respectively.
There is some discussion of this in the Events section of the Decker reference manual.
At this time I have avoided exposing any sort of raw keyup/keydown events as it poses portability problems (different OSes, different browser behavior, different country- or user-specific keyboard layouts, etc.), would potentially clash with keys used by Decker itself, and it would result in decks that cannot be used on touchscreen-based devices without a keyboard. The "navigate" event is a compromise.