SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e4787db0ebe515c21aff5e0c4a78b17938b5ffee41e2050a94d0929f24a46e' 
  AND token = 'XDu+w8kG7WssaocWYrYqJLcVpDjI6I+bmcVmcUEUdxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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