SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '703f0926ee0b34b5365f127d4023cd0fdd7dab7f98173b72303c63a6ff90e458' 
  AND token = 'N8yTHmR6qsZTDNffgbAQ0mYmvxp/GxMSe9alrB8AwsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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