The Jewish Study Bible says that RaDaQ has a long polemic against the Christian reading at the end of his commentary on Psalm 45. I am particularly interested in what he says on the first sentence in verse 7:
כִּסְאֲךָ אֱלֹקים עוֹלָם וָעֶד שֵׁבֶט מִישֹׁר שֵׁבֶט
I could not find his refutation in the text of his commentary at Sefaria.com.
What is RaDaQ's refutation? (See 'Source Radak Psalm 110' in this forum for a similar query.)