SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a21a301c5ff0299be151d343864918ef2fb0baed3d7a7495d89ee632dcb2bd7' 
  AND token = 'jnY7q2oPUbgb4C26DQfdX9tqq8rVKqxvAf1/lQdrUkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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