SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c5b3c7aecb0972a01e673db606258f347472b79497555e8e6070ffdc0551bd' 
  AND token = '/V5CuKwNzFJGlZIacPyeiWRNrnTBWj3bIHv5ZP3/HFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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