SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce39608df29c3d46aa3cf53e1d5d27bcc89b693f54bfa1194bd06435ebfa79e5' 
  AND token = 'krHlRYS78rnY3Vo5kWxXN3ogS18pU70deUufltYFnJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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