How can i get data widh key

i want to find data with key from google datastore

in normal RDB

select * from items where key = '123124124234221' 

in GQL Query

SELECT * from items WHERE __key__ HAS ANCESTOR KEY(item, 123124124234221)

it's work!

but in nodejs

let query = datastoreClient.createQuery('items')
  .hasAncestor(datastoreClient.key(['item', '123124124234221']))

datastoreClient.runQuery(query, (err, entity) => {
  if (err) { reject(err) }
  console.log(entity)
})

result is empty []

please help how to get a data with key in node

via JinHyung Kim