SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91bca034885ddbe8f95134cdca219b05bd7cb8786313b1f8b24d2a6c272f5d9' 
  AND token = 'ok7siUS9sQUTVmBAdZRv6QXqJMsQRJzRFx+ZYzEtOm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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