SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a207659a56b75c20c86a7ba23643a057c40e9fe54261ca1fda850110ad6d6c90' 
  AND token = '1lvepRSg2DBj0FytmJUU3hQp0AkSejXnr4Kl5bDuFuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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