SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78df623f80bab35935d0a74a61f44d810020f4c61dba82b93e43dced68c682a0' 
  AND token = 'cQ4lpiW3y0AKc0WaYzjONhzZuDxFiOrpg55dKe//fNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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