SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6889d476802dbbb31be7aea2e620b045d1029bddfd233eb7c14fa56f5b7202f' 
  AND token = 'DVbgkWvQUnf6phlkq6/n+FaOCQNI2P18BbnMamOzHVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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