SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f0a645b9658bbf7f4aa10cee60edbf5ffdfc4a862c35d405c8145cd5808393' 
  AND token = 'PtMvw+Kw/dARPXwDEaXR0mdhjki/0ihhtkVarzvDCzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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