SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db5fbbdba7c00d13c3c41a5d1ec5e25fdb81e27298a4a39f4fe6d6da277be36b' 
  AND token = 'XEPh6jVJjms5rqvNepLW57JG4TbPZ7pgbWCGpBqSl+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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