Every hour you have the option to collect a key pack. Your hourly key pack contains 3 keys.
Hourly packs contain one of the following combinations:
3 red keys (most common)
2 red keys and 1 green key
2 red keys and 1 blue key
1 red, 1 green and 1 blue key
You can head to the Maze Shop to spend your Lambo Beakers and increase the hourly pack for a set period of time.