SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f24b251d7b7e262405b56235e5981401411c3669958c27f1d1676304e915c9dc' 
  AND token = 'USbo95XxFvdf+9OWoWn5g9XUL5lII+82oKweMP7lRv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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