SELECT 
  b.*, 
  d.*, 
  c.* 
FROM 
  cscart_bm_blocks as b 
  LEFT JOIN cscart_bm_blocks_descriptions as d ON b.block_id = d.block_id 
  LEFT JOIN cscart_bm_blocks_content as c ON b.block_id = c.block_id 
  AND d.lang_code = c.lang_code 
WHERE 
  b.block_id = 683 
  AND d.lang_code = 'se' 
  AND b.company_id = 2 
  AND (
    (
      c.object_id = 8365 
      AND c.object_type like 'products'
    ) 
    OR (
      c.object_id = 0 
      AND c.object_type like ''
    )
  ) 
ORDER BY 
  snapping_id DESC 
LIMIT 
  1

Query time 0.00041

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE b const PRIMARY PRIMARY 4 const 1
1 SIMPLE d const PRIMARY PRIMARY 10 const,const 1
1 SIMPLE c ref PRIMARY PRIMARY 4 const 5 Using where

Result

block_id type properties company_id fpc_exclude_cache lang_code name snapping_id object_id object_type content
683 products a:4:{s:8:"template";s:41:"blocks/products/products_multicolumns.tpl";s:11:"item_number";s:1:"N";s:17:"number_of_columns";s:1:"2";s:23:"hide_add_to_cart_button";s:1:"N";} 2 N se Similar products 0 0 a:1:{s:5:"items";a:2:{s:7:"filling";s:7:"related";s:5:"limit";s:1:"0";}}