SELECT 
  cscart_product_files.*, 
  cscart_product_file_descriptions.file_name, 
  cscart_product_file_descriptions.license, 
  cscart_product_file_descriptions.readme 
FROM 
  cscart_product_files 
  LEFT JOIN cscart_product_file_descriptions ON cscart_product_file_descriptions.file_id = cscart_product_files.file_id 
  AND cscart_product_file_descriptions.lang_code = 'en' 
WHERE 
  1 = 1 
  AND cscart_product_files.product_id = 95878 
  AND preview_path != '' 
  AND cscart_product_files.status = 'A' 
ORDER BY 
  cscart_product_files.position asc, 
  cscart_product_file_descriptions.file_name asc

Query time 0.00066

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_product_files ref product_id product_id 3 const 4 Using where; Using temporary; Using filesort
1 SIMPLE cscart_product_file_descriptions eq_ref PRIMARY PRIMARY 9 toolboxdigitalshop_dev.cscart_product_files.file_id,const 1 Using where

Result

file_id product_id file_path preview_path file_size preview_size agreement max_downloads total_downloads activation_type position status folder_id file_name license readme
219267 95878 RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.mp3 RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital_SAMPLE.mp3 19819937 2881036 N 5 0 P 1 A RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.mp3
258387 95878 RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.mp3 RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital_SAMPLE.mp3 19718144 2881036 N 5 0 P 1 A RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.mp3
219268 95878 RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.wav RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital_SAMPLE.mp3 130517432 0 N 5 0 P 2 A RRB003_-_Dean_Richardson_Stu_Angus_-_Set_You_Free_-_Resurrection_Digital.wav