SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bcbc804dc6670551f03c6175bff0bef5ddc2b16a93a21235a274badf51ca38a' 
  AND token = '/8xrlwmrR6xV//ieGqc8JJlK83TOMDhLFaVnl4HTrcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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