SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe02345d065424e694809a97d2e5a2416f4889270479d12af3f5e046fcdab03' 
  AND token = 'W6hGY+KJc1FJzTj2GQ+Ipk3ch5OCB2vfrZdVqDoDOP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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