SELECT 
  cscart_profile_field_values.value_id, 
  cscart_profile_field_descriptions.description 
FROM 
  cscart_profile_field_values 
  LEFT JOIN cscart_profile_field_descriptions ON cscart_profile_field_descriptions.object_id = cscart_profile_field_values.value_id 
  AND cscart_profile_field_descriptions.object_type = 'V' 
  AND cscart_profile_field_descriptions.lang_code = 'fr' 
WHERE 
  cscart_profile_field_values.field_id = 52 
ORDER BY 
  cscart_profile_field_values.position

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "read_sorted_file": {
      "filesort": {
        "sort_key": "cscart_profile_field_values.position",
        "table": {
          "table_name": "cscart_profile_field_values",
          "access_type": "ALL",
          "rows": 9,
          "filtered": 100,
          "attached_condition": "cscart_profile_field_values.field_id = 52"
        }
      }
    },
    "table": {
      "table_name": "cscart_profile_field_descriptions",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "12",
      "used_key_parts": ["object_id", "object_type", "lang_code"],
      "ref": [
        "multi_vendor.cscart_profile_field_values.value_id",
        "const",
        "const"
      ],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(cscart_profile_field_descriptions.object_type = 'V' and cscart_profile_field_descriptions.lang_code = 'fr')"
    }
  }
}