You pick a reward and pay its price in keys, see Crate Types
Prison progress crates
Progress milestone crates
Rewards for Prison progress
Eggs
Prison egg crates
Prison crates that hatch minions
Seasonal collections, pouches, lootboxes and most event crates open anywhere: right-click any block while holding the key. Utility crates such as the Vote and Koth crates open at their crate site at /warp crates. The tables below mark every crate whose key can be used anywhere.
The tables are generated from the live crate settings: every crate, its rewards with their chances, rerolls, open milestones and guaranteed rewards. Crates used for testing are not listed.