SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dff34de4b1c730a8af9c701f8369a836abdc76c9ec25bdbffd333a57cf21597' 
  AND token = 'Qw3viaqAh1rbBUfWAgFuBokgHpTNx773X1u6x+Kt27o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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