SELECT 
  variant_id, 
  yml2_unit 
FROM 
  cscart_product_feature_variant_descriptions 
WHERE 
  variant_id IN (
    '4793', '4775', '4786', '4772', '4765', 
    '4764', '4790', '3953', '4791', '4792', 
    '4778', '4766', '4807', '4763', '4783', 
    '3745', '3719', '1938', '3709', '4754', 
    '4862', '2886', '1934', '4753', '1913', 
    '2162', '2375', '4867', '1895', '1858', 
    '1862', '1882', '2398', '1878', '2970', 
    '1909', '1941', '1880', '1910', '1869', 
    '3096', '3084', '3099', '3103', '3098', 
    '4981', '5074', '5138', '4983', '3093', 
    '4980', '4979', '3102', '3101', '3092', 
    '4917', '4913', '3085', '5029', '3090', 
    '4922', '5063', '5139', '5019', '3086', 
    '3087', '3686', '3089', '4880', '4974', 
    '3104', '5034', '3091', '3088', '3097', 
    '3094', '3095', '5008', '3100', '2982', 
    '431', '2989', '3619', '3074', '3700', 
    '3049', '3694', '2030', '1942', '1856', 
    '1870', '1859', 'Y', '94', '93', '3047', 
    '3073', '3072', '2992', '1931', '3606', 
    '1860', '3623', '1959', '1979', '1881', 
    '1897', '2399', '2567', '2928', '1899', 
    '1898', '1952'
  ) 
  AND lang_code = 'en'

Query time 0.00097

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_feature_variant_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "rows": 113,
          "filtered": 100,
          "index_condition": "cscart_product_feature_variant_descriptions.variant_id in ('4793','4775','4786','4772','4765','4764','4790','3953','4791','4792','4778','4766','4807','4763','4783','3745','3719','1938','3709','4754','4862','2886','1934','4753','1913','2162','2375','4867','1895','1858','1862','1882','2398','1878','2970','1909','1941','1880','1910','1869','3096','3084','3099','3103','3098','4981','5074','5138','4983','3093','4980','4979','3102','3101','3092','4917','4913','3085','5029','3090','4922','5063','5139','5019','3086','3087','3686','3089','4880','4974','3104','5034','3091','3088','3097','3094','3095','5008','3100','2982','431','2989','3619','3074','3700','3049','3694','2030','1942','1856','1870','1859','Y','94','93','3047','3073','3072','2992','1931','3606','1860','3623','1959','1979','1881','1897','2399','2567','2928','1899','1898','1952') and cscart_product_feature_variant_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}