Social and Political equality is something that each individual will have a different opinion on what it even is. It is for this reason that one can never fully know or understand when equality between the two exists. It is not likely that we will ever see complete social and political equality.
No, there is not a way to know when social and political equality exists, because equality is a subjective idea. Each person can have a different opinion as to what constitutes social and political equity. What is equitable to one person might not be to another. There will never be universal agreement as to what constitutes equality.