SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a61887eebba07cb6cdbd7eb2c273d70419c209071daec2a68b3d9f48c95c007' 
  AND token = 'kncv2XsZr+U3Q8mdu6Y1F/cJfUEMvykf9gCaZ6YM5kY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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