SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '49f5e7441e070e1e88d8b83866db8a896128bf5714f1b92be58bc0f1ed7f3ff7' 
  AND token = 'xB++VlFePMxclgIsWSTjgCA6d300pNyAg0XU9dPgiZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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