SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '478d2f9fe6196532713980f2eab0a4cae89575dadba1d62899fc9e6ebe49703d' 
  AND token = '+z9cFws6g4oUQoTCYrCXrorardMSUntqJgFasYh0TYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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