SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5e838728f377109ae176eda3785a37074825412b0459fc1bf146b348540e12a' 
  AND token = 'e9a2W1gnaS7nJ7ULoXmAFGyECiZExnoLuWS/9uSxT8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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