SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '470cae8587280b9fa282e6ce8da92a764e9034b52aa1636a5fc13aeb62fc8508' 
  AND token = 'YybBYaeNmxHGakOv1vW4vUlC4O+SCEcQQYis0+QGScc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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