SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e978680b51fe54e3ab808d1995ba5afc3077eb3b0ba9b66fbabd932c9cbf43be' 
  AND token = 'wCdrz2IjBu9S/Zi6cHshY4uEVg40CAh4tF6kwQtQVho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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