SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d344a8a035d399beafa8f2b709390cc409e41df7e3fc24afba02c94b635aa73' 
  AND token = 'a6zThH/jmpCzq+ph30JH2FNuDJ0f1LbZ4opEdn5Dawo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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