SELECT 
  attachments.*, 
  attachment_descriptions.description 
FROM 
  attachments 
  LEFT JOIN attachment_descriptions ON attachments.attachment_id = attachment_descriptions.attachment_id 
  AND lang_code = 'en' 
WHERE 
  object_type = 'product' 
  AND object_id = 323389 
  AND type = 'M' 
  AND (
    usergroup_ids = '' 
    OR FIND_IN_SET(0, usergroup_ids) 
    OR FIND_IN_SET(1, usergroup_ids)
  ) 
  AND status = 'A' 
ORDER BY 
  position

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.38"
    },
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "attachments",
            "access_type": "ref",
            "possible_keys": [
              "object_type",
              "type"
            ],
            "key": "object_type",
            "used_key_parts": [
              "object_type",
              "object_id"
            ],
            "key_length": "95",
            "ref": [
              "const",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "8.51",
            "cost_info": {
              "read_cost": "0.25",
              "eval_cost": "0.01",
              "prefix_cost": "0.35",
              "data_read_per_join": "231"
            },
            "used_columns": [
              "attachment_id",
              "object_type",
              "object_id",
              "type",
              "position",
              "filename",
              "filesize",
              "usergroup_ids",
              "status",
              "file_type",
              "url",
              "on_server"
            ],
            "attached_condition": "((`goimagine`.`attachments`.`type` = 'M') and ((`goimagine`.`attachments`.`usergroup_ids` = '') or (0 <> find_in_set(0,`goimagine`.`attachments`.`usergroup_ids`)) or (0 <> find_in_set(1,`goimagine`.`attachments`.`usergroup_ids`))) and (`goimagine`.`attachments`.`status` = 'A'))"
          }
        },
        {
          "table": {
            "table_name": "attachment_descriptions",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "attachment_id",
              "lang_code"
            ],
            "key_length": "9",
            "ref": [
              "goimagine.attachments.attachment_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.02",
              "eval_cost": "0.01",
              "prefix_cost": "0.38",
              "data_read_per_join": "66"
            },
            "used_columns": [
              "attachment_id",
              "lang_code",
              "description"
            ]
          }
        }
      ]
    }
  }
}