Problem with loading products (speed of website)

Hello,

I have problem with plugin on my website. When I have active plugin few category of products on my website are loading verry slow. All working well if I have your plugin turned off.

Can you please help me with that?

It loading slow these category:
https://goldencykas.sk/kategoria-produktu/diamanty/

But some category are working well.

The page I need help with: [log in to see the link]