SELECT 
  * 
FROM 
  cscart_product_feature_variants 
WHERE 
  variant_id IN (
    2998, 4796, 4804, 4775, 4772, 4764, 4790, 
    3953, 4792, 4777, 4778, 4766, 4763, 
    4818, 4800, 4783, 4801, 4787, 4773, 
    4776, 3745, 3719, 1966, 1938, 3709, 
    4754, 4862, 1978, 1934, 4753, 1913, 
    4867, 1895, 1862, 4755, 1939, 2970, 
    1987, 1970, 2178, 1910, 5137, 346, 548, 
    365, 1575, 222, 1510, 500, 524, 1856, 
    1859, 1870, 0
  )

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_feature_variants",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 54,
          "filtered": 100,
          "index_condition": "cscart_product_feature_variants.variant_id in (2998,4796,4804,4775,4772,4764,4790,3953,4792,4777,4778,4766,4763,4818,4800,4783,4801,4787,4773,4776,3745,3719,1966,1938,3709,4754,4862,1978,1934,4753,1913,4867,1895,1862,4755,1939,2970,1987,1970,2178,1910,5137,346,548,365,1575,222,1510,500,524,1856,1859,1870,0)"
        }
      }
    ]
  }
}