Even though it appears on collections of symbols sometimes, the Crux Ansata is not a common Masonic Symbol. It is part of the regalia of the Women’s Grand Lodge of Belgium (see below) and is part of the decoration of the temple of the (semi-Masonic) women’s organisation Vita Feminea Textura.
The above can be seen in the Museum of Freemasonry in Brussels. Their catalogue has the following text (translated from Dutch):
Chronological collection of different jewels of the Women’s Grand Lodge of Belgium. On top one sees the badge of the Obedience.
Below is what appears to be a Templar jewels collection. There is also an Ankh there.
Not unexpectedly, the Ankh also features in the Egyptian themed rite of Memphis-Misraim. Also see winged Ankh.
Top: Wikimedia Commons
Middle: display in the Museum of Freemasonry, Brussel, Belgium.
Bottom: photo from online auction