SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b3464d56db08d3e0fe8c3af42cab0fbae1c0dc9db6b0c77f58fd13c4b2fddbe' 
  AND token = 'UupOfjpemCuhYzG5809nZUB6bkrfiqEKCYCZMbt6mfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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