For what it is worth, two year old bell pepper seeds have germinated very well for me. Three year old bell peppers only gave me a germination rate of perhaps 10%.
OHI I just remembered! Tomato seeds have the reputation of being hard to kill!
One time they tried composting the wastes from a sewage treatment plant to see if it would be a better method of disposing of the wastes from the cities, and they got a BEAUTIFUL crop of tomatos on the field that they used to spread the compost on! Apparently the tomato seeds had survived the human digestive tracts AND the composting method they had used!
I suspect that your tomato seeds will be fine!