SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cf5a690ab9c76215e09a5bfb28cab9e970cc9bb2d33b1470b0c78eb3db50e6' 
  AND token = 'WAPTGNWunq8CdIINbP2/XeR0hlldJqcdybMST3ioZPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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