SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '8c71ec8b049acae3739ef2a9b22be74fbec0f1315c0b1e724d7a8fa4795781ab' 
  AND token = 's5sKEmZG4yGJQmy2PqLDMkeTC579XvfXqQ2L6xC1PZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00765

JSON explain

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