SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    12885, 12887, 12888, 12883, 12890, 12878, 
    12881, 12886, 12892, 12893, 12894, 
    12896, 12899, 12901, 12902, 12903, 
    12905, 12895, 12897, 12898
  )

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 (12885,12887,12888,12883,12890,12878,12881,12886,12892,12893,12894,12896,12899,12901,12902,12903,12905,12895,12897,12898)"
    }
  }
}