SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdd79ca2a335b1b04681451c31f3a8fd70902c028c77e52a21a4a46fee513558' 
  AND token = 'B+qCtcAtFIUd3+rUz8IbskznSxsGln0bZPcfp+MFiZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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