Sandbox

SELECT 
  items.chain_id, 
  items.product_id, 
  items.products, 
  items.modifier, 
  items.modifier_type, 
  items.date_from, 
  items.date_to, 
  items.display_in_promotions, 
  items.status, 
  descr.name, 
  descr.description, 
  p.company_id 
FROM 
  cscart_buy_together AS items 
  LEFT JOIN cscart_products AS p ON p.product_id = items.product_id 
  LEFT JOIN cscart_buy_together_descriptions AS descr ON items.chain_id = descr.chain_id 
  AND descr.lang_code = 'ru' 
WHERE 
  items.product_id = 8216 
  AND items.status = 'A' 
  AND (
    (
      items.date_from <= 1757192400 
      AND items.date_to >= 1757192400
    ) 
    OR (
      items.date_from = 0 
      AND items.date_to >= 1757192400
    ) 
    OR (
      items.date_from <= 1757192400 
      AND items.date_to = 0
    ) 
    OR (
      items.date_from = 0 
      AND items.date_to = 0
    )
  )

Query time 0.00051

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	items	ref	product_id	product_id	3	const	1	Using where
1	SIMPLE	p	const	PRIMARY	PRIMARY	3	const	1
1	SIMPLE	descr	eq_ref	PRIMARY	PRIMARY	10	stroysan.items.chain_id,const	1	Using where