SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73dbf9e7249b19c497b19e22406c5f872579528854c6d68af9da4521f02c6b79' 
  AND token = 'EGbguijGh3kVGmHmfSIghXUkr9HtdCZ4XRac5o9jcLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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