SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90894e5b21a890d2860ca027aff2fea4c1fe51273894e68f191f606f65cb1aa2' 
  AND token = 'XGRz5EHZRVmFi7TvFJVhz1jCfi2FNwRqaMaFpBz4Lgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables