SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    6091, 3287, 35730, 43825, 36272, 47657, 
    1586, 40761, 2961, 2135, 2870, 34548, 
    40929, 45587, 49185, 44951, 6544, 49290
  )

Query time 0.00387

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rows": 18,
          "filtered": 100,
          "index_condition": "cscart_products.product_id in (6091,3287,35730,43825,36272,47657,1586,40761,2961,2135,2870,34548,40929,45587,49185,44951,6544,49290)"
        }
      }
    ]
  }
}