SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00511273def96f938e396330dfe6400dfcaa9ad10beb4939b7a06a1924552ff3' 
  AND token = 'HkbGUx+lfSTvTVZaLtfqhTgGUwB+XUuRXxiAyoaJsw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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