SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43818c7a93a3af09102c536949e7bc76a0d689bc8b83c7587c486149448770e5' 
  AND token = 'LEia4eT++Q/uGJWipjQzBx4owLTMr3n6WXgoXuHuitc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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