SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '375eb28676c5c48f1de97009616fa3b7c82a6b2762ebc5a280a71934b35f2e2e' 
  AND token = 'pR2Gwbk9ctqKzuu5SGsbUUWacWb7oKAX6VEkJ/angrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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