SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ddf80cf4cb79defa5d39aaefcf14d175fc58c4231b3105ae1323f5a565a46be4' 
  AND token = 'OnGtYHslpiNiUFgJ3NNr7lMMM0qV0JuXZVyCW8rZsHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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