SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88c3c04ea668e51110c50d59353975fdb32591b6d1b4ee3e247d592fa04a7ca8' 
  AND token = 'NYj7+E8C29T8rFxQ1+vIo4/2j/wVMQvDLzVzvknnvDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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