SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '009f8f518ead8961270f505aacf68db665a86e4b7d34d364ff50896034b5b493' 
  AND token = 'wb+Jr3FXPhbniTum9UJPLehVGkofK21AQLrWPQ2QBKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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