SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6427dbdf3f19167c3ac28554e551d52878da355fe919b0d4506c24e70aed6c29' 
  AND token = '35Fqku7dXv4juXEhDWwO3SAPn+lL2WEnTRIpv/pdqRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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