SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe18d74e708e2b6d271130e737185bb5c03ac40803ad154f1608f52f8dcd7d08' 
  AND token = '197LB3sDK8YGyZYShXkz/vdDjIZJNhMs/wYoGU/0zcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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