SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78b9c8f4d05acbe57b43f165475b9ca8118b45af55d160cfdf86d908823f6594' 
  AND token = 'Y8sXtcfO/ojm4YBhEF1f5o8lvvWhlULRQExBtKMyK64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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