SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f4975d8a938c3d5553b1f161436ed9b9c5dd61acf8d635bc2a7ca64f125a22e4' 
  AND token = '+Vaf1k2RdAj5EZBUFeZaIYnB9w1tc5jTO9f+mpVVPso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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