Hi,
There are no direct way to restrict a payment method to a product as you can see if you edit the settings of a payment method via the menu System>Payment methods.
However, there are ways to do it in an indirect way.
For example, if you don't use the "dimensions" of your products for anything, you could set dimensions only for that specific product and then use the "minimum volume" setting of that payment method so that the payment method would only display if that product would be in the cart.
The weight can potentially be used in a similar way, however a product with a weight will require shipping, which might be problematic based on what you're selling.
Also, a payment method can be displayed or not based on the selected shipping method, and the shipping methods can be restricted to warehouses, and products can be linked to warehouses. So that's also a path to display a payment method based on the products in the cart. However, warehouses also have implications for shipping methods so that might not often be a good solution based on the situation you're in.