SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eb297b8769fe26e2031238e2470ad7e3f8bd1de1be13a58840bad3c0e72b60b' 
  AND token = 'RxWx7HugRSIUyQCsO/kGFF0So5ezREdKpqH1+G0NYJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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