SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '264ca8512f84b8ae9a7ff7cd798b35a1cfc59e76363edb30b37693a3cbffa3b8' 
  AND token = 'WWdJ6Ou0tif8koM+rArkA7cFbn/ikqvrlfUUkKBeesw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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