SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c82dc7aa7ef08731f8d826ce4dd843e3a7d09451ae287479032ee60a6038e1e' 
  AND token = 'oiMJtV6+K+qFa2AAa80GJBbE70ewNeRaMP0bHQuIe/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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