SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2ffe0ba3bcce4e149c27d76fe470e5afc4aadc3ea22e3d67731c0fb3ccfddd9' 
  AND token = 'uWukBBYnSOt1iqgUp8eY038zanwHOdUhfbmPe7WCihQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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