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 
  cscart_product_files.product_id = 672 
  AND preview_path != '' 
  AND cscart_product_files.status = 'A' 
ORDER BY 
  position, 
  file_name

Query time 0.00021

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables