SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bead57da3def28851eafed2f784796756bf28c1b0c10cbaa61968a95667ce6d' 
  AND token = '17TEvDPx8MqyRDe3RU3hG6r/LQTkdIwB12+cwEHsWBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}