SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af9dae22a83b8927214426f0b613f5e98b351a3038127c3d2fa4e47e4fc39ae' 
  AND token = '15V9LvBR3JNB4olSQ9L/qfGBjY7oVhqZR+7FNWRfQXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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