SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    5568, 5574, 5571, 5573, 5569, 5567, 5572, 
    5570, 5581
  )

Query time 0.00024

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": 9,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (5568,5574,5571,5573,5569,5567,5572,5570,5581)"
    }
  }
}