oh i'm sure you could rig some kind of u-bolt/clasp with a small master lock, but any redneck with a rock or a small hammer could get in with a 5 second delay. I've seen 500 ski's on the water over the past decade, not a single one had a glove box lock.
when I go out on the water my box has $20, my ID, a $40 gps, and otherwise, all worthless crap.
don't worry about it. glovebox theft isn't common.