SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a76c8471807d5d42c25bee1d2e9058c7504358e7666a1d7d7350da6feb03a72d' 
  AND token = 'uc35aFTy3hRvsy8Dhe//wTu/KoXZtnT2iv44moJEwAU=' 
  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