SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2355bac5ae045fb17cc23636c98d86948c3e95658a4fcc6fdc287a762fe6bdaf' 
  AND token = 'ThPTS4FH4FS5pl9eJ2BKvbKbJOJdil0a+pp2/CK5FwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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