SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6596becf703833f3663e674b2279d715835ff98e1d6b7b147a0ed77d6f2abdb' 
  AND token = 'yk8HTzabciZ+BdVpFmzjA3zjDuvRIPHPpgrV76XSBOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

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