SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b4a9db71855efda9a9faf57261828a439fb5697a4c463c7d44fe68f6600d29' 
  AND token = 'yfTtddDd4agVBwmYayO/HSD0HVvSpAwI+mw0TEl1bQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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