SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c4e9bf2ee097161627a56036b7ecf7541ffd5d52eba7b30f7f7f31012a83ec4' 
  AND token = 'lwznqR/tafKXDsDvrvLLrIHx6qCwTu7WRJ57Pyd/nIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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