SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34bcdb14406129261c0d2236345d6971b90120cef134064d4fdc34c21966eeb1' 
  AND token = 'qzpfiCSB93RlfTTATD/gHxlE5Wb+A9ztFCOXM4x5Ltg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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