SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1409520441b2d0052fb32ae49a29110096ffa59935a62a7de283b889921ee447' 
  AND token = 'XMVl0ICogYE8EsKmXuEFnkzDLwCwZnAQqfNjHfHuDWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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