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SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '68d8bd11fc5753f336f523ab39711882a1eab85eaaadcc24fc4d0b9a63fc49eb' 
  AND token = 'NQL7LyN7hNoOJsnZuNJiDmLgJ3SPg2kxA4zUtQTh/0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00785

JSON explain

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