SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b5833b42083132c1df4e36c42ab47877c5b18f32fb558d29c3754c1ff0a26f' 
  AND token = 'VOewEfbE5AQmaEHFA9IWBtu93C6OrpLLCf1+b6Pabyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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