SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '17437e4663790614eca740de4fdec17d7fd7842db93b6176cad6b93600aaaf39' 
  AND token = '3wLnzzy+gjXEwJU7YAqrF5oUx5b7e39tG6dPr74y58E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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