SELECT 
  cfv.category_filter_value_id, 
  cfv.parent_id, 
  cfv.parent_name, 
  cfv.order, 
  cfvd.title, 
  cfv.hint, 
  cfv.is_any, 
  cfvd.lang_code 
FROM 
  cscart_category_filter_values AS cfv 
  LEFT JOIN cscart_category_filter_value_descriptions AS cfvd ON cfv.category_filter_value_id = cfvd.category_filter_value_id 
  AND cfvd.lang_code = 'en' 
WHERE 
  1 
  AND cfv.category_filter_value_id IN (331) 
ORDER BY 
  cfv.order ASC

Query time 0.00122

JSON explain

{
  "query_block": {
    "select_id": 1,
    "const_condition": "1",
    "table": {
      "table_name": "cfv",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "4",
      "used_key_parts": ["category_filter_value_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "cfvd",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "10",
      "used_key_parts": ["category_filter_value_id", "lang_code"],
      "ref": ["const", "const"],
      "rows": 1,
      "filtered": 100
    }
  }
}