SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e3f9535002e706d7a2219eb1e13309f0eaedfeb040a086737898b527145e3f' 
  AND token = 'DAavHdwKoCh2iF14kTFNhbyq4rA8/udjsiEQB0yv7+s=' 
  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