SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '272c7965d831e9ad6b75bc94805f30d90ef7bb837d802cabb785e9b131e90496' 
  AND token = 'h4AjgNP//1Kq7FSt1T7qgp2RcbsvUVMoHnRzU1maIVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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