SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f4f25771f87c49325c7ac2c54736a965bd0cf33f1d9c02bd03581da35af93e0' 
  AND token = 'OqVXhhav/Ved0qgi8vAmmr9v5BKhehtud0nAJLMXhHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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