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SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = 'ef9a935143b8a7f1e65021a6d4bcdc6347638a167845d0ad1734dad12b3cb65f' 
  AND token = 'b7A1n+kv0lKAWiQIZfGWgslcKUTM24vM1kXrJB+DPM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00782

JSON explain

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