SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb0257f8c236d61cb4e79750efb8fb52380364372f9df2e8ff265a0794707275' 
  AND token = 'ToRgTCJMtKEcRgRuw+hIUMZMVDHzuC5p9dAYx3qEO/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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