SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '889400e69abd6f4b6c53bac3848a27cd6d6af177e4cedf81f53ab42d958c0eee' 
  AND token = 'WKd8uTAXER/oDMHlpfuVGxCYWOMcMIRhIJ6DHDdMN6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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