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 = 303 
  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 0.00036

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 4 Using where

Result

block_id type properties company_id fpc_exclude_cache lang_code name snapping_id object_id object_type content
303 html_block a:1:{s:8:"template";s:21:"blocks/html_block.tpl";} 2 N se Stegu Montagefilm 0 0 a:1:{s:7:"content";s:472:"<h2>Interior stone</h2> <p><iframe allowfullscreen="" frameborder="0" height="720" src="//www.youtube.com/embed/tstfzyQhkWo?feature=player_detailpage" width="1280"></iframe></p> <h2>Exterior stone</h2> <p><iframe allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" frameborder="0" height="720" src="https://www.youtube.com/embed/pg6_4OI9o3M" title="YouTube video player" width="1280"></iframe></p> ";}