SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2728a66399c73fb18ff7d5cf312eb0e9de8398ec14c2ae9ac85404893758fe12' 
  AND token = 'Rug5SWhHKbwifYjOuJDB3uQJhIhEPF2axl/JtjTFcO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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