SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35dbaea1f1958699e6e363d34f1e827d100149c3033821c75aa441ca52356206' 
  AND token = 'MN7QuuwPiOGXGfaZbip9iOLMFwtQQxcF6n+B9adNhhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00134

JSON explain

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