SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b9a2c1983875d42d4b91c3561f2fa32241877d1c582d54afcde3afa4a04b3dc' 
  AND token = 'nYw9CyGmWX8y/7lOz5iwFDdNhDnSQ5GSSSfW5lgcJAY=' 
  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