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 = 68199 
  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 0.00040

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 2 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
130001 68199 DB025_Asylum_-_Whats_Your_Jam_-_Dan_Dyson_Remix.mp3 DB025_Asylum_-_Whats_Your_Jam_-_Dan_Dyson_Remix_SAMPLE.mp3 16155887 6382936 N 5 0 P 1 A DB025_1_1_Whats_Your_Jam
130002 68199 DB025_Asylum_-_Whats_Your_Jam_-_Dan_Dyson_Remix_-_Drop_Bear_Digital.wav DB025_Asylum_-_Whats_Your_Jam_-_Dan_Dyson_Remix_SAMPLE.mp3 71302820 0 N 5 0 P 2 A DB025_1_1_Whats_Your_Jam