SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    1825, 1826, 1827, 1828, 1829, 1830, 1831, 
    1300, 1301, 1302, 1304, 1303, 1812, 
    1808, 1807, 1813, 1836, 1860, 1861, 
    1837, 1851, 1853, 1838, 1839, 1840, 
    1841, 1842, 1843, 1844, 1845, 1846, 
    1847, 1848, 1849, 1855, 2915, 1857, 
    1862, 1835, 1834, 1863, 1809, 1864, 
    1150, 1152, 1149, 1151, 1148
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.08425304,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["product_id", "lang_code"],
          "loops": 1,
          "rows": 48,
          "cost": 0.08425304,
          "filtered": 100,
          "attached_condition": "cscart_product_descriptions.product_id in (1825,1826,1827,1828,1829,1830,1831,1300,1301,1302,1304,1303,1812,1808,1807,1813,1836,1860,1861,1837,1851,1853,1838,1839,1840,1841,1842,1843,1844,1845,1846,1847,1848,1849,1855,2915,1857,1862,1835,1834,1863,1809,1864,1150,1152,1149,1151,1148) and cscart_product_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}