SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '90fad1b4c28aca7ac6c27a28df717a51db5296f53c2859354c869fed58ecef3d' 
  AND token = 'EcDGVZWttNrNci5eIqmadWwpWJWurHnkznaSxSOEHss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00827

JSON explain

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