SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b17be4d8396a2d73da48246990d0fa911109c985a00b9ee7259e54e911134c5' 
  AND token = 'HFb22H/bYSFvYTKSin+uMZrl4jZlhghXC9/f9LBgYVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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