SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'def7f12943a55488521ddf3b184fa5239bcdbf95254cbb4687929bd851fd2275' 
  AND token = 'pxVCdpIGE3WLJKssV0jAGo9cLveMnitSXdGO4kYFjBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}