SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '584c974e14993170533d96ba23394c7906bff759fb8d62af463e96785fbae057' 
  AND token = 'Lx/KdMq4lTKM3jy4Kt9nc8DVycQhj3Z44H9HwXf7CKM=' 
  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