SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '973726d82c28223b51e4e154ddd0cbe07adb5035379095929db720fbfbadda25' 
  AND token = 'zytVpWRAZJEjB4egYN6sPlm1RyWDRe2vwhF/udswbK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00758

JSON explain

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