SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8526abc26a40a33f2db5077398ef408a953ea29e51f4dc4fb514cd34802c56f' 
  AND token = 'DrRAchYwKpCtFBECuT9oJ8fnrsxdUBftkV8rVbHUwHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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