SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412f6d4635352af995a193aad3f25adb7aaf061a5af4b4462c813725bacef72d' 
  AND token = '8rAxJz82NLvge+GC7PGVzLPKJRu9ygyQrU+Z4quAglM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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