SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd375dd828b2f16060a8332852eade203439bea7210c86eec8bc5af1df02e237c' 
  AND token = 'u3s1NF04dxOq/4aXt4KntaZHXb4S29UDv3ZCfHtCWYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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