SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '573066b432ff95d23e304fb324899a4241efe60aa7ab71973f3b1f57706ce7ff' 
  AND token = '6LXWMwlrCHEBFIVGQGf+4NE+DwK7uhxQfn50heop9VU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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