SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8048278ba43466869142483a428f8a1e7aa0962e6c265e44342a8dca2af70b89' 
  AND token = 'hHZiAnjUWl6CMcw3QoLu7e6EBBoISeZkUV+hwjM8spk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}