SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f6c8ea98e53e9ffc516e52bf51b559595682b8f9d7f946abe8cbb22e630b11' 
  AND token = 'q6w6qChppZoClKhxFwL6fbcfY9eCl9ZOlzk0Qto/7KE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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