SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '900b8ac6b64a0344e5f11dec219e8d93b738c5e1c8bce613ed89543022b04a7d' 
  AND token = 'ORM8XEvY1aBn+nrVNUP6D/tYD2ov7uKQjcaY8jZVAJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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