SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a82dab9c4bb3b102674815f04eeba4d6426401c08a0b9f16e73816a9515eba3e' 
  AND token = 'D7yA7/rdML9V4lV5yES5LXEKPwqBn/FsHSr/N2fWuDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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