SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1727845129b3e5ad80e884f9a4157df90a3b1906157130f981442902bfac7ebf' 
  AND token = 'yqwXdwV9ThSIFPl3DkZ3j+nO4VEUe1SajkVJNDsml5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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