SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3521226cb16d37b03d01814be3e998ded193131fbc94ee55720c649cb9b0e72' 
  AND token = '4a6LbgAXQsC9CBe7Pju2J1KgJTFebHT9S19Rtc7J9PI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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