SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b509abfd92d82bcb22494825a19037e32af298c7a5f3152461ddb545a60c09d' 
  AND token = 'GrH9BG/2ICn/VzCWhAfZSgdMnopx+ocnklHZ8mA8MZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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