SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b08e9f5db5c5400f5fd1c77329f6feada1a084ff00debaeb79ec776f761aa3d5' 
  AND token = 'hqS71W/l9BKTyl/umcMNer6e2T+Y2MdeX6+seXB90lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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