SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ade840d9b1493e3d8f99aaa04613a591532715275191ef4379e4e84a1b86d88' 
  AND token = 'MlX2mwH3n207PE0YanAfFF9wiNK1BWeOdgjPhFVdKSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}