SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea2e424aae7d027649a6dc30bbd4ef01316491dcc17a3d10634d639be0c4407' 
  AND token = 'jb6VZ4SpRPYRKWSUdA0MmF1L079OlbiljxWMARkqFHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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