SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75f689adbb04ddf572015cbdd6d8a72d4862d3836e689f7a5c13bec84437444' 
  AND token = 'Tpl9ZcblMLEfVgYUQ7GNQiKmYRIMCXprrSch58SB/a4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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