SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df5f3fb4fd5bf8ed0fedabdaa26d9cfe6300e105279eedeb40185b573591ef48' 
  AND token = '6hSfW/AP6mqQcYMRLiwlnzwh+nnCF+S5Ke6RaAAMyc0=' 
  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