SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4168a20b5f45a76526a58e4f10416f81160af65e5a2406c666974ddb51985ee4' 
  AND token = 'is4snoMSRkJ6tC6DJYTj0iWPjlR7uafrLPUkqU/JpfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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