SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c10678271b97d40d79811617827f472d928c105b378d4bafd41f013e603c5b' 
  AND token = 'rnZFBF7SKG/Al50LnaPKdDO6gPjcggQRzsVFBekq6uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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