Seems to be a simple format. I think Excel kan import this as a table. Only problem is the Base64 encoded point. I am not sure how to handle this. You could write an Excel macro to expand the base64 and write the point x,y (longitude, latitude) to an x and y column. The Excel file can be imported in MapInfo and mapped then.
A small MapBasic or .Net application / plugin could easily be written to import these directly into MapInfo.