SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b8fb5a97e84dda97bbbf8b83f8d80e70b9659fbc622928ed27435c893562757' 
  AND token = '5gC0gFq42+AayF7pjZ+9VVu0M5Cbu15fwicHTadq3pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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