SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5deb9ed140cbf57b35283863295f6fac47f591967d0b90ca04f5c95b267c2bf' 
  AND token = 'pQNnlwbyJUVvz8PSt28pmylZEv18ayiVdDPvNUgmKu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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