Transact SQL :: Execute As Credentials

I have created credentials:

CREATE CREDENTIAL myCredentials WITH IDENTITY = 'domain.user', SECRET = 'password';
Now, I would like to execute query with this credentials:
SELECT a.*
FROM OPENROWSET('SQLNCLI', 'Server=Seattle1;Trusted_Connection=yes;',
'SELECT col1 FROM [myServer].[myDb].[dbo].[myTable]'
) AS a;

How can I do that?There is no EXECUTE AS 'myCredentials'...Should I create some new login first, bind it to this credentials and then : EXECUTE AS 'myLogin'