SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e8a96f823e6e4ea7664344e3e68403501513088bbe038a85997d86daffb1806d' 
  AND token = 'KqUZYNpJy6ZejkbnBUILbrE5xf+UFkbqs6e1WKSNJuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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