SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7917f943551dc0f92f506ea1f8b15303298654ee448a9645ab061333d276917d' 
  AND token = 'UiTpKu4Bgd+1lkGYoTA5UJXSI/g4zlgvZuBy6VbCQxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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