SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    10845, 10844, 10843, 10842, 10841, 10840, 
    10839, 10838, 10837, 10836, 10835, 
    10834, 10833, 10832, 10831, 10830, 
    10829, 10828, 10827, 12642
  )

Query time 0.00047

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 (10845,10844,10843,10842,10841,10840,10839,10838,10837,10836,10835,10834,10833,10832,10831,10830,10829,10828,10827,12642)"
    }
  }
}