SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1ca369858437791bac80281f2b8d458fd565a1febd5481d7c37c80cb5af33c' 
  AND token = '9+WNXBPQuA3PwKzHK4gNBDx9cS0YPTBGpEc6wC9QrJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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