SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f3cd807fbc01a0cac4d7e780fb4b768573fc013d0b3250240fef94bb98eb71' 
  AND token = 'cjMX+1tmY5X0dCk7uQQyNW+JYR+jYTpgoPkgC83MCec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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