SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d3e82fde8ab5278499537cc6ba01afbb64236765e8e95ae038dcde2c1c46078' 
  AND token = 'IQY9LYqkBWap2QstnydwC4SgHqTdIfi0bqHRdkKEU68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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