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SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '63d81d58cf3408c95d89e35cd70921042e2b286c20f99378f0dbe43c91a12a82' 
  AND token = 'KlENVaFbRc0SwoGsyYORgxK8hBSxXuquHIy179Y8g48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00747

JSON explain

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