SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '741ad1aa5bc87ad71b9de4277d080f608880e79bc2ae9f831a1112d9eeb26474' 
  AND token = 'WoSekgHXWQQzQY6wDwE6BKI5Mf0ReCpH4g0eMFya99E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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