SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28b0e1bda4b9df908702b098bdf9cf8c92df403ec69af45dfbf2f79c148cf628' 
  AND token = 'hZ+Ah9okb8JOv9ZtWBvVsJZhBmFm+AuXAIpJz2Vyr/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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