SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '70565f5ea52df758ae5179d37c9b1b1c72da8cd5b318307b9b1dff20239a6ab7' 
  AND token = 'VDXbORJTQXQw95Fr5tnLjbGRjEjBOomvRe5wj1WBJjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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