SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '653cdbe025215f83133f06b98c4b3b3a9677152192b28617fef66637a7193685' 
  AND token = 'HTQQx6OmLreuHAX7eKdZTYtpS+poHUbhUyfy2swNUls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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