SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91801e94e62abc47647d7fab8e4153d77457bee057fb48b36605524ea2f28a63' 
  AND token = 'ZLGpdd/FJobOx4AcC9Nju/o/oo+VyWUZ3q9tXBhKKMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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