SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5875c1d9ca0e09e929f155b2f8f358e7def6c5e2349bcb03935cbb513209f69' 
  AND token = 'MHDQ6Z30MMXmpQdPL4mzy/IV2z4d2sanHADwCVg/m+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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