SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861d3249af4b63f3b0a439d50e481a45eefa7d1e97f38bfbdf4fbed12827f846' 
  AND token = 'ys4+uZiAaOENtr4+ML4GZxPftpUrYOFpUMHKfWwOqo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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