SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52f555e4617bf0e6f1ea2d4589d04a36aa45f5535723aaf87840d9d24172b5a' 
  AND token = '34XURymcg2poxs0IU+NfrJhvo6AHfL/GLnbVSB148L4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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