SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbec692268bff53134fcdf07308684ff7ff58105abd0bad0b42df60723193019' 
  AND token = 'fCKpDCfNolxM+ISaeVrNfTZXCx+79vQv11HxwXvCjOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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