There is a condition called 'Compare current frame of 'Active' to value under 'Animation' on any object you select in the event editor.
Start with that, then find out the value of the animation you want to start the jump on.
But you don't want to make it only jump upon pressing a key + a certain frame is playing because then you would have to time it perfectly.
What you want to do it make the game remember jump has been activated (via a flag perhaps) then wait until both jump is activated + animation frame N is playing before the player jumps.