EDIT: I tried using a CTE on my previous answer which was incorrect, as pointed out by @bummi. This option should work instead:
Here's one option using a CROSS APPLY, to kind of work around this problem:
SELECT st.Value, Constants.CONSTANT_ONE, Constants.CONSTANT_TWO
FROM SomeTable st
CROSS APPLY (
SELECT 'Value1' AS CONSTANT_ONE,
'Value2' AS CONSTANT_TWO
) Constants