SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e688102ddf9ff228688c1a2a0378257ff889777de6b174cb3f4b8efc8f158211' 
  AND token = 'huPnjQFMWvx1PNB4yZmIAYBai0lR+dkIq/9zPQtBNWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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