SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85832bc768eb0b94458f635f0eab79b8c466add268107cb965f7c8a7da572c76' 
  AND token = 'SZRfHezdvNtTJSh6VGS944p/qq6B47NzgiYzCIiF2PY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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