SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f6176d732e8bacec84eb45fa52b333f94b63acde1bf8fba328f51024bf20c08f' 
  AND token = 'kkqVtLyGGh3bHtaVTqiwwO/WCHXOyJH6QJHQ+vmu1rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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