SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc6df4bdf92d15baaecd964696985cb16d4162f6b120fad2ae9626c66b232c50' 
  AND token = 'khFo8+4NHpkuPH3sIX46Oty+orE1TQ5l++89l7Hf3Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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