SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ce50f7b337a11bad388c111a5323c7ee4571cafff1bdcf60c8fd6ecaa10b42b' 
  AND token = 'k6OgGKzJgjthXeqUrBrf+qrqAVFZGUvvvRHU5hE7nJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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