SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fef42f918cd5bb81fcadaf4b7f121471bae46f1bd43f96d627f60dc6516abe7' 
  AND token = 'rE9642TlEHVenmxPZlwipdMleP4aVq1mxp1z9ReusOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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