Crates contain a range of rewards from money, fly tokens, tokens, boosters, tools, and weapons.
You can check your crate key balance with the /keys command. Crate keys are virtual, and not physical items.
To open a crate, go to the crates with the /warp crates command and right-click a crate.
To preview a crate, go to the crates with the /warp crates command and left-click whichever crate you would like to preview.
Certain crate keys are awarded for certain reasons. The most common way to obtain crate keys is by voting and reaching the vote party.
Ranking up will also award you with crate keys.
Donators are also awarded crate keys for supporting the server.