SELECT 
  bundle_image_id, 
  bundle_id 
FROM 
  cscart_product_bundle_images 
WHERE 
  bundle_id IN (2, 3)

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.81"
    },
    "table": {
      "table_name": "cscart_product_bundle_images",
      "access_type": "range",
      "possible_keys": [
        "bundle_id"
      ],
      "key": "bundle_id",
      "used_key_parts": [
        "bundle_id"
      ],
      "key_length": "4",
      "rows_examined_per_scan": 2,
      "rows_produced_per_join": 2,
      "filtered": "100.00",
      "index_condition": "(`atulecarter_new_april_setup`.`cscart_product_bundle_images`.`bundle_id` in (2,3))",
      "cost_info": {
        "read_cost": "4.41",
        "eval_cost": "0.40",
        "prefix_cost": "4.81",
        "data_read_per_join": "32"
      },
      "used_columns": [
        "bundle_image_id",
        "bundle_id"
      ]
    }
  }
}