SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff4e2608a86dcffd1a5486b811830fbd1474af9d7e5c7cf1f426564050417897' 
  AND token = 'u0ho2wbfryvXYdEgfZGLN9gkhoJ/55xEOrv7g6gh7k4=' 
  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