SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83e73afe76648aac44aae26de27e425bfe8f911875829d6dd4a63a4dbb78c4ba' 
  AND token = '1ZPseOBCh5+ssr3U6JIbPYxZMyhSX1hkmhkgElKBho4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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