Node.js SDK - authentication accesKeyOrToken

Hi,
where I can find accesKeyOrToken to use AccountClient from node.js sdk. I thought that it’s access keys from application section on TTN, but it doesn’t work - “401 unauthorized”.
Basic case in NodeJS:

const { account } = require(‘ttn’);
const { accessKey } = require(’./config’);
const AccountClient = new account(accessKey);

const getApp = async () => {
try {
const app = await AccountClient.getApplication();
}
catch (err) {
console.log(new Error(err));
}
}

getApp();