SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0868637e01a49edb5780bf3d9b61acb42cb79e98a3b3efdda02ed49ac03c912a' 
  AND token = 'U0hETdz676g4GC/Mx7jNeoRiw2uGdxrzDG3qQbbEtjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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