SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '558e1298cc882e406aef11b279ddaa16e57cb315f0c5b6b254faf6cede5f2cb5' 
  AND token = 'syJCFkDMiWRrqmdyu2fAme358qRS3QQovUANmr59/9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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