SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c84bc31aeedc84ab52afe313c9aa4bcbd0ef626333d4a9fafc346effd3db992' 
  AND token = '/2RXDyIftXa9IE/lnA8qLyi4Br7rL/1T5Ss9DAzDc1s=' 
  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"
    }
  }
}