SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ffb35a549fc9d53e5a78e03614598d9527d806ba815226b2ca1554721477e9' 
  AND token = 'VTdamJhPJzE/rqB1W3EC7H5ex5XYjG5UEH21zXJzitI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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