SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6911360f480e6dcd5fdb30a9872fd05259a3441a6f9faf488bc56a18ad860c29' 
  AND token = 'uAKPV+1HdvMbs29mh7W5XrW/baqAYChMkACrMCjfPcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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