SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd027697a03a28a1e278ae2f2d7b1a5b2a4bf7fc93950cb288f39f56fb046f766' 
  AND token = 'GNiTY4bVz6iiph3xQzuM6Clt5cAqKiTOAnEansvliq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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