SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7780910a5043da911f44c6c0282ee70e6fe7a9a66a6671b687bb1c75ec94a5' 
  AND token = 'SCny+RwSmMB1Iv6CGnpTWvhf55LNLdycOtUQd7x8GSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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