SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b25c71c8c7a67816079b6eec368e383dac9028c8569f494ddba757ce4f98cdb3' 
  AND token = 'jwdQcO+MfAJkt+2MVHh+3KTFxegI9fksVLr1qnG3KVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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