We do not have a shiny key for mystery crate, and there are no legendary drops in it so we can't have it be the same as every other crate, so here's my idea for it:
It would be very expensive (I'm talking like 30c) and give a random reward from the previous crates that is NOT obtainable with normal keys, such as the mythic items or 40 crates opened reward. If you decide to do this, maybe change giveaway rewards to 2 normal and 1 shiny keys, as the usual giveaway. Please consider this, and thanks for reading.
It would be very expensive (I'm talking like 30c) and give a random reward from the previous crates that is NOT obtainable with normal keys, such as the mythic items or 40 crates opened reward. If you decide to do this, maybe change giveaway rewards to 2 normal and 1 shiny keys, as the usual giveaway. Please consider this, and thanks for reading.