SELECT 
  cscart_products.*, 
  cscart_products.ebay_status, 
  cscart_products.ebay_template_id 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    18301, 18302, 18303, 18304, 18305, 18306, 
    18307, 18308, 18309, 18310, 18311, 
    18312, 18313, 18314, 18315, 18316
  )

Query time 0.00048

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 (18301,18302,18303,18304,18305,18306,18307,18308,18309,18310,18311,18312,18313,18314,18315,18316)"
    }
  }
}