SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '968c316738bb7e7eee8a350dd71aa9c64ce7920b16d9d4f0d7a782b278cfa941' 
  AND token = 'welOVfP4Fyd+2kQLmh5XtCw2KZPJCvvjiqftBD/PPuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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