SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9a5a7c150b23dd3b5bb3cf258b8681a34fa84ff4f0a5079cd0d01b7d9fa389' 
  AND token = 'snG0JrCvPccNmBG0cHzyXlVsfrnEoUO2+VwAplMOaRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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