SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35fc8575535d7b751894614a7f2913c7cbc4ff22268372581dc02ff7afe8a2ac' 
  AND token = 'GU+khE219u9zPe1e6SrSSl4fG9wjPW0/O2rkKAnZd4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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