SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb3970e08dfae0491abda93e14dabcc01c8038fee2f688f8d8a882c375a66b98' 
  AND token = 'vSEUXReLf90iMx0hEbA6tj1HxTaHZUd8gLli+XghiUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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