SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248e84c2f4bf6f10919d03984a51875ea1c18d8cbafc035bb9cca1c8a4accd19' 
  AND token = 'XyozHORXQ2qXDLnFpvqW9zeHHpgtVzLSO7ReXc7JcoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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