SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e6b4acb9c5803689b955dafbb1d2a28f63c253ccbb97535e89bee949c05121' 
  AND token = 'NjJVoKgfSEJ6ZXYTzmOKWJveP7N/h5ihAmTwfvhBVzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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