The Hadith of Abu Hurairah is Hasan Gharib. This is acted upon according to some of the people of knowledge. They dislike selling and buying in the Masjid. This is the view of Ahmad and Ishaq. Some of the people of knowledge permitted selling and buying in the Masjid.
In-book : Book 14, Hadith 125
English translation : Vol. 3, Book 12, Hadith 1321