SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '26eed948d0945785b7aea161162df293e8fb93d8f63e8341653dd98055350fb4' 
  AND token = 'Piiq5bYhvZSBpV23HSRemx2QXMXHj0hzuIKyXbU4L5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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