SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef6edbcfcd79e033da11309d627f194bb526efd3b91a514faca16136da1f8536' 
  AND token = 'jHY1CBetqg9XMSgIm35CkQxLosrHaME6Xuy21ITlisQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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