SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '86ab402006a2d0e877dbd0db201936826b5915d32261af149f4adc933c8d20ac' 
  AND token = 'ncGi3JXYQVfbbzhDBMLsQ38Gt1PpKXoYjGykfO123zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00763

JSON explain

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