SELECT 
  c.product_id AS cur_product_id, 
  a.*, 
  b.option_name, 
  b.internal_option_name, 
  b.option_text, 
  b.description, 
  b.inner_hint, 
  b.incorrect_message, 
  b.comment 
FROM 
  cscart_product_options as a 
  LEFT JOIN cscart_product_options_descriptions as b ON a.option_id = b.option_id 
  AND b.lang_code = 'fr' 
  LEFT JOIN cscart_product_global_option_links as c ON c.option_id = a.option_id 
WHERE 
  c.product_id IN (400) 
  AND a.product_id = 0 
  AND a.status = 'A' 
ORDER BY 
  a.position

Query time 0.00050

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "a.position",
      "temporary_table": {
        "table": {
          "table_name": "c",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "product_id",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "ref": ["const"],
          "rows": 4,
          "filtered": 100,
          "using_index": true
        },
        "table": {
          "table_name": "a",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "c_status"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["option_id"],
          "ref": ["multi_vendor.c.option_id"],
          "rows": 1,
          "filtered": 72.80000305,
          "attached_condition": "a.product_id = 0 and a.`status` = 'A'"
        },
        "table": {
          "table_name": "b",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["option_id", "lang_code"],
          "ref": ["multi_vendor.c.option_id", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(b.lang_code = 'fr')"
        }
      }
    }
  }
}