Closing a LTF card which you don't need/don't want/don't use will boost your credit score.
Because It shows that you are less hungry for credit.
So unless there is a good incentive to keep the LTF card, you should close it to boost your credit score.
After I closed HDFC Millenia, Amex MRCC, RBL World Safari, RBL Platinum Maxima, SBI Simply click, SBI FBB, etc; my credit score jumped an incredible 98 points!