SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83959eecd2c46a6dbbf91af87cebf78e43ca5ecbc37a14e814810ee4498ef874' 
  AND token = 'K4btYW3Iyatc32VhmAMjIdyDSgmEUPFSUQuf3VDMQmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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