SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1d96a87589f9233b40d654c56fddd95effb289be673be1bd145baa1e3d2cbf' 
  AND token = 'NAq0NO4kkRlFf93xykEHdlYXZ5IqtPvIwjl9jQmjDTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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