How do key fragments work with honor?

I hit level 5 honor several weeks ago, and ever since I've been level 3 honor I've gotten about 3 keys (9 fragments) in total. I usually get a least one honor a game, but I seem to never get key frags no matter how many wins I get. I have 9 unopened chests due to the lack of fragment drops while a friend who plays less than I do has 10 keys (30 frags) leftover because of the amount of drops he's gotten in the past. Beyond wins / premades, is there any other factor into receiving key fragments?