SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f21e5d825238ed01540f1f7c5e5346887bb58877f55c92d52eea394e8bcac6f7' 
  AND token = 'HeX8pkXLWzkJTKPsp8P1ZYffG3RtJYBNtJHbxMdR0kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}