SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5015371bce6c4de533d2d9a5af915689090953cafbab6018a5d46044c320389c' 
  AND token = 'mD7uQ0Mr6oweoRIiVk2V8p9Jn/+gbJBcIApsnaUqDig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

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