Set a modified mesh (with shape keys) as default mesh

Set all the values on all the shape keys to 1, or to whatever you want in your final object. Click on the down arrow (see pic), then on New Shape from Mix (see pic)

Highlight, one at a time, all the shape keys (including the Basis) and click on the "minus" sign on the right hand side (just above that down arrow.) You'll be left with only one shape key. You can export that and it can be imported as the end result you have just exported, without shape keys.