The naive way to add approximate timing annotations is to block the SystemC kernel in a transaction until the required time has elapsed:
sc_time clock_period = sc_time(5, SC_NS); // 200 MHz clock
int read(A)
{
int r = 0;
if (A < 0 or A >= SIZE) error(....);
else r = MEM[A];
wait(clock_period * 3); // <-- Directly model memory access time: three cycles say.
return r;
}