SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99caefadd4030fecfbada29a413f16c416f587ce5a5eedeb09d55fce702f7f44' 
  AND token = '7tegz7rKEoBLCERRW1jN4QjHXcAtwltUYLtJwOxBzK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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