SELECT 
  a.shipping_id, 
  a.company_id, 
  a.min_weight, 
  a.max_weight, 
  a.position, 
  a.status, 
  a.tax_ids, 
  a.usergroup_ids, 
  b.shipping, 
  b.delivery_time, 
  c.company AS company_name, 
  storefront_id 
FROM 
  cscart_shippings AS a 
  LEFT JOIN cscart_shipping_descriptions AS b ON a.shipping_id = b.shipping_id 
  AND b.lang_code = 'fr' 
  LEFT JOIN cscart_companies AS c ON c.company_id = a.company_id 
  LEFT JOIN cscart_storefronts_shippings AS storefronts_shippings ON storefronts_shippings.shipping_id = a.shipping_id 
WHERE 
  1 = 1 
  AND (
    a.company_id = 3 
    OR a.shipping_id IN (1, 8) 
    AND a.company_id IN (0, 3)
  ) 
  AND (
    storefronts_shippings.storefront_id IN (1) 
    OR storefronts_shippings.storefront_id IS NULL
  ) 
ORDER BY 
  a.position

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "a.position",
      "temporary_table": {
        "table": {
          "table_name": "a",
          "access_type": "ALL",
          "possible_keys": ["shipping_id"],
          "rows": 4,
          "filtered": 100,
          "attached_condition": "a.company_id = 3 or a.shipping_id in (1,8) and a.company_id in (0,3)"
        },
        "table": {
          "table_name": "b",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["shipping_id", "lang_code"],
          "ref": ["multi_vendor.a.shipping_id", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(b.lang_code = 'fr')"
        },
        "table": {
          "table_name": "c",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["company_id"],
          "ref": ["multi_vendor.a.company_id"],
          "rows": 1,
          "filtered": 100
        },
        "block-nl-join": {
          "table": {
            "table_name": "storefronts_shippings",
            "access_type": "index",
            "key": "PRIMARY",
            "key_length": "8",
            "used_key_parts": ["storefront_id", "shipping_id"],
            "rows": 1,
            "filtered": 100,
            "using_index": true
          },
          "buffer_type": "flat",
          "buffer_size": "35Kb",
          "join_type": "BNL",
          "attached_condition": "trigcond(storefronts_shippings.storefront_id = 1 or storefronts_shippings.storefront_id is null) and trigcond(storefronts_shippings.shipping_id = a.shipping_id)"
        }
      }
    }
  }
}