SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fdacbbc94f9ed77eba088feb169bd65ae8598e4360f875d5ee6ff123c9aa538' 
  AND token = 'xlXWGVIadsluf3nlacwXtRf0cluKTq1w7fKrPtSJdqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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