No they aren't.

Has, by itself, is in the present tense. For example, "He has four apples", or "She has a talent for mathematics", or "He has a new car".

However there are times when it is used along with another verb, and it is the other verb that sets the action in the past. The word "has" usually makes a connection between those past events, and the present. For example, suppose that someone is walking 50km, and has reached the middle of his walk. You could say:

"He has walked 25km so far". The verb "walked" refers to the 25km that he walked before now; that is, the distance that he walked in the past. The word "has" indicates that he is doing that walk at the moment.

Other examples are "he has been here for 4 years" or "He has arrived in London". Again, it's the second verb that is referring to the past; "has" is simply an auxiliary (helper) verb that ties the action in the past to the present.

This form is called the "Present Perfect", if you want to search for more information on it. I suspect that this is where you got the idea that "has" refers to the past from.

It's really helpful