SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b85250ed2ae94cda5e6d22b87f225a7bbb974e0a257787fa4121196d7476b480' 
  AND token = 'MFNzZmwGqIkpIl11qEbTJtdA6hkvznETiqTVvzbGnjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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