The Book of Mosques and Places of Prayer
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ أَبِي مَسْلَمَةَ، سَعِيدِ بْنِ يَزِيدَ قَالَ قُلْتُ لأَنَسِ بْنِ مَالِكٍ أَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي فِي النَّعْلَيْنِ قَالَ نَعَمْ .Sa'd b. Yazid reported:I said to Anas b. Malik: Did the Messenger of Allah (ﷺ) pray while putting on the shoes? He said: Yes
From Sahih Muslim, whose reports the scholars accept as authentic.