You only have the @ri addressing mode (where ri is r0 or r1), there is no provision for indexing, so you'll have to do that by using an add instruction. If you have the index in the accu, it would look something like:

add a,#base_of_table
mov r0,a
mov a,@r0

In other cases, especially if you use a counting loop, it is sometimes enough to load r0 or r1 with the base address before you enter the loop, and increment or decrement r0/r1 with every iteration.