SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a723c9f66760dcc91f5faf84a3aa46041486960988b7f4f0a5bd41450ed395be' 
  AND token = '7bHPPg3Nk7IoheGBbgGQ1+psex7AlCMYvoi3bBPXoXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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