SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f53803bfc07f97dd60a0628f2fd558aa132a067915780eaccc38863d58bebb2' 
  AND token = 'ByhAvItw4BIuzGKJs+YOkUSP9h8yu8Usr9SzlW9ZRww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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