SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd25428f7d0940c872ac8bdabbea40b73dc8d53626586a36622e3a9793e57bf27' 
  AND token = '8u+crCncfG0oLhjeJe8CLWOypsELDjtFhGqCVlcQEpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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