SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99aeba66ec7233ae4bf24b5267b16beaea881c541acd782cc7a43595482e946e' 
  AND token = 'doxx0fSVipwMjbrzuIBwz/ufB2S0ENkNNEdZpUQkYQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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