SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9ff1768c62c8fc93ab60ca040157ddae403d50a0d255d0ad02bd94194ef7ea6' 
  AND token = 'HKrQGvoRx/7muPJLT0kpbNfcWQKDOVPPrucI67jtnQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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