SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06b01e5cd0c9be62fda3811efe06b120b2006b89848074cfedca6b128a8936bb' 
  AND token = 'MbHiTzcSYqWowAACqv+Korw0swMT+WdX5RdGRHYlvzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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