Finding if a specific key contains a specific value in a Hashtable?

Is is possible to check if a Hashtable contains a specific key with a specific value?

For example, if I had something like:

var table : Hashtable;

table = new Hashtable
({
     "Backstab" : 1
});

How could I check if the Backstab key contains a value of 1, so that if it does, I do something. The scripting reference says I have ContainsValue(which simply checks the entire Hashtable for a specific value), ContainsKey(which simply checks the entire Hashtable for a specific key), and Contaisn which is the same as ContainsKey. Seems to be no options to find whether a specific key contains a specific value. Can anyone help me out with this?

in C# you can check it using

if(hashTable["key"] == "value"){}

JS is usually the same or very similar.