SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c493b207b8aa1eeafbca93acaa540e76cc5d04217bb54acecb15347e98f401a' 
  AND token = 'LeXHWzTBnp9RnOZfKt/atOjCkStfe4cKZL6Zyo/kopM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}