SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016fe9a13e93d03d31ed49a032b023c80a63cd25f5169de46bf6bd0dc954ea78' 
  AND token = 'gJ3HkMdZa+nH66CxmJi2gnvAI9pTyehr3ZmekXgex5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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