SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cde232ab18298bed6a69549d6f75e64617b26cd64b0f5d866a2ddc3033a7cdf' 
  AND token = 'kkqTKUknOYlfj4uwadUxhthqm4cTeRJpkIH2qTrKcFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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