SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4c0183e6433749ff69cad6a573482f1099426d3463badabcde7ecf99b12d28' 
  AND token = 'u6W3Z0lxyMkp9Gs9fjCYs+oJXeJH+rUy36yKK7nNJOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}