SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84e032269b6fa9032987110575836c4be755423bb919c22738dcf0f57ea4a849' 
  AND token = 'isci8feSmhNInok21czawPw/bAFiAwnzukUGugzh2nI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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