SELECT 
  cscart_products.*, 
  cscart_products.ebay_status, 
  cscart_products.ebay_template_id 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    8608, 8609, 8610, 8619, 8620, 8623, 8624, 
    8631, 8632, 8635, 8638, 8639, 8658, 
    8659, 8661, 8667
  )

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 16,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (8608,8609,8610,8619,8620,8623,8624,8631,8632,8635,8638,8639,8658,8659,8661,8667)"
    }
  }
}