All jackpot prizes are available with the unique Key Pays!" feature. Prize symbols with credit values, bonus pays, or progressives are won by landing a key on reel 1 or reel 5 and all credit prizes are doubled if a key lands on both.
No, there is no way to predict when a slot machine is going to hit a jackpot or to determine which machine is going to be lucky. Slot machines are programmed to use a random number generator (RNG) to determine the outcome of each spin, and the RNG generates random and unpredictable results.