SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    9846, 9845, 9860, 9859, 9858, 9857, 9852, 
    9861, 9862, 9847, 9863, 9856, 9855, 
    9838, 9849, 9850, 9853, 9842, 9851, 
    9854, 10263, 10264, 10265, 10266, 10267, 
    10268, 10269, 10270, 10271, 10272, 
    10273, 15943, 15951, 15952, 15956, 
    15958, 15959, 15944, 15960, 15961, 
    15962, 15966, 15957, 15965, 15945, 
    15938, 15968, 15946, 15947, 15949, 
    15950, 12520, 12497, 12528, 12512, 
    12511, 12527, 10580, 10579, 9936, 9931, 
    12521, 12504, 12502
  )

Query time 0.00089

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": 64,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (9846,9845,9860,9859,9858,9857,9852,9861,9862,9847,9863,9856,9855,9838,9849,9850,9853,9842,9851,9854,10263,10264,10265,10266,10267,10268,10269,10270,10271,10272,10273,15943,15951,15952,15956,15958,15959,15944,15960,15961,15962,15966,15957,15965,15945,15938,15968,15946,15947,15949,15950,12520,12497,12528,12512,12511,12527,10580,10579,9936,9931,12521,12504,12502)"
    }
  }
}