Hi,
Surely! I recommend checking this knowledge base to get the best possible speed for your server setup.
I especially recommend the first few suggestions, including using the index table engine. Those can have a huge impact.
Ajax Search Pro runs on your local server, it does not use any external paid services like other plugins. For that there are no subscription fees, it is much much cheaper, however the performance will depend on your local server speed.
Make sure to try the suggestions, they will make a difference. Let me know if you need help with any!