SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52aa7991463969c9b432a70f786bb305fd0fdbfec7cf490e0ca93c046d7d4b08' 
  AND token = 'qA2lQyGFFCWQU5ZMmRA0g4TJhLqZzZicPYa+ttPHKHk=' 
  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"
    }
  }
}