SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2c00c122cce8934480b0c70fc352530010d503f2797424e216a638465ced5b8' 
  AND token = 'MCC/lyB5ter2obClKJcWmnhHmJPy+1CmPGqtSEvyGvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

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