Idk if I’m blind but I don’t see it anywhere is ki booster time, 3 days in game or 3 days wether u are on or not
3 days real time - if you get it, make the best of it. 
there should be a clock running on your menu screen (Days/hours/mins/seconds)
Sometimes it wont show…as son as you notice this, restart the game and it will come back.
I mentioned this int he bug section but never got a response…but Im sure they are looking into it.
if you bought a booster, make sure that clock is always up before you continue to grind!