SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a25a33a97a726434c675c60219020669321eb00c5f8a596da5cc0c753f6e1304' 
  AND token = 'vAfnUdfVK24B2UrjfKZcSiY6nfXuvZwLoQJ0sj0AlUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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