SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e97a65736831ec7040956ec65782b1fb4d23aa1796cc86496284912ec03adfe2' 
  AND token = 'K//tYBWag0q9/blxtvqLGRODaK5BOj/wpTZL4FCqUKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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