SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa7820d0a38ccdb9573310b412b9d46093da5be08c7cdf854ff289516bf26807' 
  AND token = '0/yrEjV9QqdGOC7RT1xDsFxsmXkjAnEVS1KBhTObGgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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