SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6994b21c4912897dbd84b9a3ec96fe0555f4f490969c064fc7efc2f6bcc174be' 
  AND token = 'UYuT9/+SmtjwSHkyFpUwZV8zBbynnXb2RdEB6hzndCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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