SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337a29b9c2d34f5e30a8e11c04bfcf9baf625210dedfffc6d1d20157dbba6731' 
  AND token = 'dqT/NmFFoopj+e9//BpPlSWpbfZDulB/BHLgAtY1cPY=' 
  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"
    }
  }
}