SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f03d5e26f9288ffc36c157e07ff729b6dd733379a2416e15fceb8489e56d15' 
  AND token = 'g+RhoBsH9iIobTAOf3aJCQuo2z+C3KOflhujEQDVRRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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