SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52dadab13fea80211b44b6654c51e9f573fb197a983dd3402a06e32ec65957a8' 
  AND token = 'i31lgwTDZRRN/wVQWha8SKxM8xiL/NIx/tN3lcC57Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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