SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    12551, 12544, 12546, 12547, 12548, 12549, 
    12550, 12555, 12556, 12557, 12558, 
    12559, 12576, 12577, 12578, 9683, 9685, 
    9686, 9687, 9688, 9689, 9690, 12560, 
    12561, 9775, 9776, 9777, 9778, 9779, 
    9780, 9781, 9782, 9783, 9784, 9785, 
    9786, 9787, 9788, 9790, 9791, 9792, 
    9795, 9797, 9798, 9799, 9800, 9801, 
    9802, 9803, 9804, 9805, 9806, 9807, 
    9808, 9809, 9810, 9811, 9812, 9814, 
    9815, 9816, 9817, 9818, 9820
  )

Query time 0.00108

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 (12551,12544,12546,12547,12548,12549,12550,12555,12556,12557,12558,12559,12576,12577,12578,9683,9685,9686,9687,9688,9689,9690,12560,12561,9775,9776,9777,9778,9779,9780,9781,9782,9783,9784,9785,9786,9787,9788,9790,9791,9792,9795,9797,9798,9799,9800,9801,9802,9803,9804,9805,9806,9807,9808,9809,9810,9811,9812,9814,9815,9816,9817,9818,9820)"
    }
  }
}