SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a492078d95a6d50a4fed051fa3b74290d49bf9f8a5ae94c28b8f49f8521a8bb8' 
  AND token = 'WMZE3xBMTzsBgBHuhHgNhrQUqN1lozUwO2jXTCgcV1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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