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 = 'ja' 
WHERE 
  items.product_id = 512 
  AND items.status = 'A' 
  AND (
    (
      items.date_from <= 1747234800 
      AND items.date_to >= 1747234800
    ) 
    OR (
      items.date_from = 0 
      AND items.date_to >= 1747234800
    ) 
    OR (
      items.date_from <= 1747234800 
      AND items.date_to = 0
    ) 
    OR (
      items.date_from = 0 
      AND items.date_to = 0
    )
  )

Query time 0.00005

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "items",
      "access_type": "ref",
      "possible_keys": ["product_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "ref": ["const"],
      "rows": 4,
      "filtered": 100,
      "attached_condition": "items.`status` = 'A' and (items.date_from <= 1747234800 and items.date_to >= 1747234800 or items.date_from = 0 and items.date_to >= 1747234800 or items.date_to = 0 and items.date_from <= 1747234800 or items.date_from = 0 and items.date_to = 0)"
    },
    "table": {
      "table_name": "p",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "descr",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "10",
      "used_key_parts": ["chain_id", "lang_code"],
      "ref": ["markins_test.items.chain_id", "const"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(descr.lang_code = 'ja')"
    }
  }
}