SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28969b992c714a606e0b357646a42e2e3faf894fe05b57f7b09640e3dfdecce6' 
  AND token = 'lkqTZiY9kvwy26zmvFK0rB/SwtOUyONmPw8fD847eZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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