If you for some reason decided not to use your daily 60 Keys (or like me are waiting for Floor 16-22 to appear) then you'll have 720 Keys. More than enough to at least unlock Axel. If you hurry, that is.
I'm sitting on (error) 404 keys rn without even fighting a single rank match. Since they started giving event items in daily gift bubbles in addition to the daily bonus, it got even easier to accumulate them.