SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a5fbeb5e029c9781949e24450e35cb7b0f4e9cd147edb5a57f5c2a061e460c2' 
  AND token = '83GrZOG4fdbVMHLTlJ0AVUP/XJVDg1OrKuHhdtQq+hA=' 
  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"
    }
  }
}