SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a5cb251971f55db79b51bb20310a141ca5086f26efd2addd02616e7fdb2c83' 
  AND token = 'xecikRDLsU4UM1QFQmnB4KQPjGcne/FeHyFgrXegDDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

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