SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87cb4a27227521d83dee7fa467f9423c2e1ae36448692147f4cf8d233962a8c3' 
  AND token = 'f0LqO2w4H1/AZb5wHD0WD56Q3lYo8sSI1Ojk2KXRx0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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