SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deee174e901ab5d2db184302345545b1c17f800e255b832420beaec93adbe7f0' 
  AND token = '8cIOS06c9mkd1QvKClwpqawXfoMLpQ1V8zFP49LwjjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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