SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '887965f2aca3ab598746419aed79e1ded0bbddbc438dde3c1ec3fc5d34a988ad' 
  AND token = 'jHOKUjHvYcW/dlztnTFafwBbSccbZ5RJ9UhXrztPrJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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