SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23e1a43ed6c0da7ae87ae779712f39319b0c4f22a4256551fb37d214fa0559c' 
  AND token = '5MQtZMb04pGxQjvbFsEBw3TakRYRuVm+B6UtKCocq4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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