How can i Improve my code (Transaction took too long)

Question

I have Enough CPU and NET i have staked 13 EOS for each and still unable to run the code. Please suggest if i can improve anything. IS there any problem of table index

Got this from developer.io if anyone can explain what is this indexed_by<"byage"_n, const_mem_fun> do and is there any mistake related to this in my code coz i have not added this

typedef eosio::multi_index<"people"_n, person, 
indexed_by<"byage"_n, const_mem_fun<person, uint64_t, &person
::get_secondary_1>>
  > address_index;

typedef eosio::multi_index<"paymentmade"_n,payment_made>paymentmade;    
paymentmade payMade_table;



void mainloan::payconfirm(double pay_amunt,name from ,uint64_t loan_id)
{
  require_auth(_self);
  auto loan = loan_table.find(loan_id);
  auto pay_date = current_time_point();

  paymade_table.emplace(get_self(),[&](auto &p){
  p.pay_id=paymade_table.available_primary_key();
  p.pay_date=pay_date;
  p.pay_amunt=pay_amunt;
  p.pay_from=from;
  p.loan_id=loan_id;
}); 
loan_table.modify(loan, _self,[&](auto& l){
  l.last_pay_date = pay_date;
  l.lending_amount=loan->lending_amount-pay_amunt; 
});
}