SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '681575658d5d6bd6f105a57acfc5581bbc5c447eddfa8e654aad1bd198b55960' 
  AND token = 'TzXHoSUXAlGG3gCDD8XSW4WkLrlNPVUUYixiZ3B+YUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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