SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '540acbdad9516687a0a61b2a4ed5ce3ac5dcdb60fd7e0474cd1f0ead6f18678f' 
  AND token = 'f1jxJ08b9Kqv4Va63CIL2Hi84zE2GxKU/c6/JnOXFjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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