SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed196526636fd3446f9c0878e8348e16055540e62e8cd0bf0786bd9dc83ac45' 
  AND token = 'NCFegOodhPrnXX9FI5D5tWp/P+7hdehWsWMokFyZ2qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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