SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6587b157d34b543277eb909489752c21cd517b40ff99a45e75a99db94d9c065b' 
  AND token = 'aSuIvTqtE/velep6ROGtOlER8bwre3/tWnCZXw7gVYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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