SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f41de0891af46bd6fb84d0e40d547b5ff794a0faf01038eb93e937a95d184c3' 
  AND token = 'uzGgH849NfqMQzrZN30nCLAti34IQiPNKJcwArieKyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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