SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2156a80fd9d47cad28903057f3691e75455add9cb44e116edfa39a9d79b359cc' 
  AND token = 'vGWwFI4KjRXC+5pyNscXZxKi9LVzEpPTgzktYm1MiMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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