SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa57eb7512490e4728bcc2d1124f93369983d499225df6e5bee9afbd13243981' 
  AND token = '2fJl48siTEsxMBNZOnqHQQiUvul9s6GH0lwHW9Z+nJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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