Will I get toilet clean when I mix sodium chloride, water and hydrochloric acid?

Don't mix things unless you know you are supposed to. That is a stupid way to kill yourself.

Sodium chloride is table salt. No effect on cleaning toilets. Hydrochloric acid will eat metals, such as the bolts in the base of the toilet, the plating on the handles, and anything else it happens to float near. Put that back where you found it and don't bother it again.

Go to the grocery store and get Pummie and a toilet brush. Pummie will scrape off any hard deposits inside the bowl. The brush removes soft deposits; use it every time you flush. It is ok to put a small amount of white vinegar in the bowl after each flush to reduce the formation of deposits due to hard water. A TBSP will do.