SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fdcd7325e563930dc4be128fc74d3f27e99eff7af6e11e80a449a84999721ac' 
  AND token = 'iqU+bKhH1bQz0nYvVlOKGov0tn82w7LQs0II5WLJCEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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