Query tune

I want the below query to be tuned. I tried with union but it's executing in more time. I've also tried with sorting the coloumns in the 2nd table.

Select a.run_dates_stations_id, a.station_master_id, a.run_dates_id,b.call_letters, b.dma_id from contract.run_dates_stations a left outer join customer.station_master b on a.station_master_id=b.station_master_id where (a.ibmsnap_logmarker= '1900-01-01 11:16:30.0' or b.ibmsnap_logmarker= '1900-01-01 11:16:30.0')

Are there inexes on the joined fields and fields in where conditions.