The plane is old and was never very popular in the US, Air Transat operated them in Canada but they were replaced by the A330s.
The only civilian operators for the A310 today are Mahan Air (they still have a large fleet of A310s), IRan Air and Afghan Air. Royal Jordanian uses one for Cargo as well as Turkish Airlines.
In the American continent your best chance to see one of these is a CC-150 Polaris from the Canadian Royal Air Force, those are A310-300 converted to Multi Role Tanker and Transport (MRTT), for X-Plane inibuilds has the MRTT so hopefully it will be coming to MSFS at some point.