-- Manually exporting a key (admin/keys_export.php) now takes it out of
-- circulation the same way redeeming one does -- an exported key is meant
-- to be handed out through whatever channel the export was for, so it
-- shouldn't also still be claimable through a claim link, or exportable a
-- second time as "unused". A new 'exported' status keeps that history
-- (unlike deleting the row) while falling out of every existing
-- `status = 'available'` check automatically -- no other query needed to
-- change for it to stop counting as available stock.

ALTER TABLE `keys` MODIFY status ENUM('available','redeemed','exported') NOT NULL DEFAULT 'available';
