Lucerne hay can still be too high in NSC's. You should either have it tested by a forage lab or go ahead and soak it for 30-60 minutes and then drain off the water before feeding it.
Also, if you are looking at low NSC feeds you will need to cut out ALL grain products---these can be as high as 45% NSC's and you need to be shooting for an overall dietary NSC content of about 12% in a horse with metabolic diseases like Insulin Resistance. You should choose a forage based supplemental feed to provide balanced nutrition when fed with the type of hay you have and that has a low NSC content.
Again, this is all if your horse has a metabolic condition. Otherwise you don't have to worry so about the NSC content but you still need to work on getting a more palatable and balanced diet than the one you are feeding.