SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '52aa8f167f82e9377fd89d654b7aa5d0177a196093bef1022a172c4a9f53d910' 
  AND token = 'xErb5YuZJnb689//+kRYHb5ML4rsHQbNk0Nl4ptNlgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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