SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2541160a9e48fe31351d8fd35eb2793967eb8f498d89b926eb6da6347e6088' 
  AND token = 'REZZvTXSZPKTRh/D/aOpks8EVHAWpon+ohMXgrplGM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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