Hello,
MySQL should be able to handle 100,000 results (and even millions) with ease. Do you have any example mysql statements being made on the website for me to check out? Is there any other tables than the one? Can I see the mysql schema (excel file)?
Looking at your website, it appears it is generating totals. If it's doing this per month for each row, that's a lot of trips to the mysql database! It may be better to precalculate these values, and have a script run monthly to generate the totals if it is working how I believe it is.
Thank you, and I look forward for the chance to work with you!