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SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = 'a77c01f3ccb66067ac046274217491b8117f2a1bc69ff6f439411762a3eb417d' 
  AND token = '4uP1lDUc3ezoPCNZMHFQ8BqvsMXkw0QjfYSWs6lem1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00774

JSON explain

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