SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a44eea35c3859a78bb7d4b2682dd13d0b09e5b0fe11f4faeff71209567f6c850' 
  AND token = '+CIQxQsWnZKiolKVth0WITD57dqeZnIG8YRgONU+rSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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