SELECT 
  object_id 
FROM 
  cscart_settings_objects 
  LEFT JOIN cscart_settings_sections ON cscart_settings_objects.section_id = cscart_settings_sections.section_id 
WHERE 
  cscart_settings_objects.name = 'storage'

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_settings_objects",
          "access_type": "ref",
          "possible_keys": [
            "name"
          ],
          "key": "name",
          "used_key_parts": [
            "name"
          ],
          "key_length": "386",
          "ref": [
            "const"
          ],
          "rows": 1,
          "filtered": 100,
          "index_condition": "(`_testcscart`.`cscart_settings_objects`.`name` = 'storage')"
        }
      },
      {
        "table": {
          "table_name": "cscart_settings_sections",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "section_id"
          ],
          "key_length": "4",
          "ref": [
            "_testcscart.cscart_settings_objects.section_id"
          ],
          "rows": 1,
          "filtered": 100,
          "using_index": true
        }
      }
    ]
  }
}