SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    6836, 6861, 6862, 6779, 6782, 6781, 6858, 
    6857, 6783, 6855, 6854, 6789, 6788, 
    6851, 6850, 6790, 6848, 6847, 6796, 
    6795, 6798, 6797, 6801, 6800, 6799, 
    6837, 6802, 6835, 6778, 6763, 6775, 
    6750, 6753, 6752, 6755, 6754, 6758, 
    6757, 6756, 6761, 6760, 6751, 6759, 
    6819, 6767, 6766, 6769, 6768, 6772, 
    6771, 6770, 6774, 6773, 6776, 6805, 
    6777, 6804, 6832, 6803, 6839, 6838, 
    6842, 6841, 6840, 6844, 6843, 6849, 
    6794, 6793, 6792, 6791, 6853, 6852, 
    6856, 6787, 6893, 6785, 6784, 6860, 
    6859, 6863, 6780, 6833, 6818, 6834, 
    6806, 6810, 6809, 6813, 6812, 6811, 
    6815, 6814, 6817, 6816, 6820, 6807, 
    6762, 6930, 6823, 6827, 6826, 6825, 
    6829, 6828, 6831, 6830, 6808, 6749
  )

Query time 0.00277

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "pfvd",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["variant_id", "lang_code"],
      "rows": 109,
      "filtered": 75.229,
      "index_condition": "pfvd.variant_id in (6836,6861,6862,6779,6782,6781,6858,6857,6783,6855,6854,6789,6788,6851,6850,6790,6848,6847,6796,6795,6798,6797,6801,6800,6799,6837,6802,6835,6778,6763,6775,6750,6753,6752,6755,6754,6758,6757,6756,6761,6760,6751,6759,6819,6767,6766,6769,6768,6772,6771,6770,6774,6773,6776,6805,6777,6804,6832,6803,6839,6838,6842,6841,6840,6844,6843,6849,6794,6793,6792,6791,6853,6852,6856,6787,6893,6785,6784,6860,6859,6863,6780,6833,6818,6834,6806,6810,6809,6813,6812,6811,6815,6814,6817,6816,6820,6807,6762,6930,6823,6827,6826,6825,6829,6828,6831,6830,6808,6749) and pfvd.lang_code = 'en'"
    },
    "table": {
      "table_name": "pfv",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["variant_id"],
      "ref": ["herbaria_cscart_4_18.pfvd.variant_id"],
      "rows": 1,
      "filtered": 100
    }
  }
}