SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7622b577c7b04cbbe9977d3fc11d8daed7fa46af0e093a89c121b728cee7b178' 
  AND token = 'p8YzPk7CYD+HWDjcmNirThUlXrsWE9LkyXrz6jXgzhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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