SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3393bb917ce9763cfb24e1f8ca593fbdc6e09c88ad7b32648111127dffd4a80' 
  AND token = 'AlvbBCxJuG7XjP2mpW8QT0cEZ5SK07qagXI/LzRgMAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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