SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9af018fea5de3b973b7f034684751082433be4d05edfd987079117c492809e9c' 
  AND token = 'iZPo9LWoiC8VDPOuQCzIKK1yn0T6FsFwKT+nqYVQLTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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