SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991c6e0098a8f9c153dfefe18f5335f5c1083f5571e8af3610bdcdb2a56d8667' 
  AND token = 'SD3zHLLENgf5Mz9nZIwV29767IayzuCC9LndFNbcpJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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