SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5c8d43e0bf178d94f55e895d4fa00c5866ee17fc141c8a054441fd275f8d45' 
  AND token = 'XMzD1wfqAVxu6aYt09ui6RLnN+5ALNsE+EX8WyINQrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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