SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a4736e6c691e0a9fab304c98f330d8a94f6fda7d4a630f807a3ed8befec5d295' 
  AND token = 'ujHeulgQ522JmFtezw5L8AG6CpRGqtTvuwguczjOUM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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