SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f204665ac9cd1ce282fb561d35426bc2e4d49a2790ebe279d32b20bd1ffe35f6' 
  AND token = 'N4pGYrJvtTv6g4Ha+Vy7qUDqVEzbjCbgoWnjLRgFhms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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