SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e737ff37d277309671791b67f8b27e827ce5deb3b751663564044752eb12111' 
  AND token = 'SLiiFH0D2HiiPkuVgHBX8YFrxWJUMzhEjypvltencEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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