SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae7ac1ba53836457e607554a5ee94996271276c49a6ad702c645fdbdf1fb9b16' 
  AND token = '1QTJ+CzLHYGqp5Ku0nQfLdDDrREgwzb85zz+5Mf2VmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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