SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b4962404c58d2a34325e3b2107a70178d7217e6670413ea6355e870b21a65c84' 
  AND token = 'pwoRW8E/kubFoV1r4U/JhGzINwsHFHfrd+B65h6+V9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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