SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff3c3c3acb428feaa017af02f8deabdf4f3aecf9f2bd02ed53b25c536d134633' 
  AND token = 'n14DdK9KBbDZY9GxmsQq/j521UbV5VFFF/ppWURRkBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}