SELECT 
  * 
FROM 
  cscart_sg_services_technologies as st 
  LEFT JOIN cscart_sg_services_technologies_descriptions as std ON st.id = std.id 
  AND std.lang_code = 'ar' 
where 
  st.id = 1

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "const_condition": "1",
    "nested_loop": [
      {
        "table": {
          "table_name": "st",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["id"],
          "ref": ["const"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "std",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "10",
          "used_key_parts": ["id", "lang_code"],
          "ref": ["const", "const"],
          "rows": 1,
          "filtered": 100,
          "unique_row_not_found": true
        }
      }
    ]
  }
}