SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e743e119885a3ef26d9d8d2342c7475878bd75bc54420501a0a25da7c570f23' 
  AND token = 'tZcFynM70epEWmc3A9KPhvjpy+MA/zh8voZMHtTqIXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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