21A. Rates of interest charged by banking companies not to be subject to scrutiny by courts. — Notwithstanding anything contained in the Usurious Loans Act, 1918 (10 of 1918), or any other law relating to indebtedness in force in any State, a transaction between a banking company and its debtor shall not be re-opened by any court on the ground that the rate of interest charged by the banking company in respect of such transaction is excessive.