SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd5d3ae9a8b220432614cd9f0b4854d042e9dc9707f780981ee0bc3bddd1339b8' 
  AND token = '3A+pmgioJZWoN3oaMG6bfUYOGN+pYpZOVlfAG3hqV+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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