SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5cf197da7470243a29d68e35148e9bfa0be6bbd8495d89985d02e2ada829f19' 
  AND token = '1qhPurFPvXNSg70HHAd0Vbd1QjY3CHFviXlq614UFvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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