SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '77642bdd1fdf3b24d12216ce444055179e8bbf1c3fc3b30694eb8dccbcabc6df' 
  AND token = 'FYW8CEQfKAdGrgiG643GGLP7KHg3kreYB8cnX1+TtZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00801

JSON explain

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