SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c92ad3404b9d5b4608e4ed2f6222401e09e5259d89053f43dde10b3b20f05ad' 
  AND token = 'cS6Qr3ae+qJepffuf+4fwqxjj7/6eRER9XfqK5CYrXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}