Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6840440529ade5366ecf20b78c7856b70a0e78dadcc8d474218fcbf367a48e2f' 
  AND token = 'xFdctVEpaZOCDpCoDMI9DYjTo2z+9zhqubc9MqZRfKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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