SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10a6df706644dc2e1274330d45a258689a4fcc73392a51750e424ec135965098' 
  AND token = 'tcDozo2m12CH+aP86ZgwTxdSaDIpwqOkuN4kbsxHx40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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