SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb37aaa45c1d9f49d764acec728b4b462e7af98f9cd5031e292efda0b1ee29e' 
  AND token = 'ism3msb70ZJB0CEQQNRRiFMyDsYiEtjOkg0C9EIHcyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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