SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a5f0799d87eeba756d36e0c12d86ea9232e9efc1b81cf9fc635c893a389395e' 
  AND token = 'mgnXnXnN9f6xeWgHRHbWPuAbatpCaP/kxmfbRpSOWug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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