SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1f43439d40844d8bff76f540a182b49928e93b8836ff859af38138933304bdd' 
  AND token = 'NOUcScF5oLUH9oiBNKIqOHBuLsbW4HPD3uoW/dWdNx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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