SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0898749cc04da519b0d9fb9aa9d834e1e36af58524e1656921e91d3ae8415f91' 
  AND token = '+LMBQapHcSrZzMq5LRNOYqfA2nQDyG40t1qCscC9ym4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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