SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c2ef309a64c305c3f7b811cc63b68d07875b1882e5fd3556b12f259c9c1fee2' 
  AND token = 'kYeFmOrI+JfrGhYFegaQWrs5epx5YMpp5sFSUBNjM4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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