SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe192c2a141ad035d86062c68a9b5c8abe9dbc2a79133b71740f164dd32e9a4c' 
  AND token = 'mJzsFUUQMgFQUTAGfub0cgxmGTuCUHNCU+VKhm/qTO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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