SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    36661, 36662, 36663, 36664, 36665, 36666, 
    36667, 36668, 36669, 36670, 36671, 
    36672, 36673, 36674, 36675, 36676, 
    36677, 36678
  )

Query time 0.00102

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 (36661,36662,36663,36664,36665,36666,36667,36668,36669,36670,36671,36672,36673,36674,36675,36676,36677,36678)"
        }
      }
    ]
  }
}