SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    15938, 15968, 12703, 10167, 10168, 12574, 
    10594, 10584, 10079, 10080, 10081, 
    10082, 10083, 10084, 10085, 10086, 
    10076, 10077, 10073, 10523
  )

Query time 0.00078

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": 20,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (15938,15968,12703,10167,10168,12574,10594,10584,10079,10080,10081,10082,10083,10084,10085,10086,10076,10077,10073,10523)"
    }
  }
}