SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a5b171bcbc9b6baba9bcf160ce68f730629d4dd5dbe593e8d05b5bb500ecbbb1' 
  AND token = 'YyrCdgDonRX+aZdosodItDvy5rKBDBlduUn9a0YX3MY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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