SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    9975, 9976, 9977, 9978, 9979, 9876, 9877, 
    9878, 9880, 9881, 9882, 9883, 9885, 
    9886, 9888, 9889, 9890, 9891, 9892, 
    9893
  )

Query time 0.00073

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 (9975,9976,9977,9978,9979,9876,9877,9878,9880,9881,9882,9883,9885,9886,9888,9889,9890,9891,9892,9893)"
    }
  }
}