SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727867b54698f91a4c10ab73b7b54bd416bce7d4480c019a300f8740fdfffd6d' 
  AND token = 'HQHHQOLgPgHsjQpGm33kKyLwSRsR6BtRk30lXb87Vk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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