SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da27d150f549b710054a5b76fe357e6ca9a49bbc7115488461c7b220d75da627' 
  AND token = 'QM8OWSwKZbCuVNMYY8Np+y6XoJsggLl8zY19X7qHT6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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