SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '6c38cbc251572f07f362685de027a8d25455997596501b44574109a354362a17' 
  AND token = 'dYOQ3tgUBFMvFhzO6s/6hrXfzJzXqxsoalTblAOHk30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00775

JSON explain

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