SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8369212d9be88b9c0385c2eedf7726b322e5fc52a4668072cbd081dbe106826a' 
  AND token = '709ngc0rjxCt7CJFr3xuddUHK+/uSGC2JD+IC+PEXy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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