SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be8287b7343e7f509c01e35de6b3b231413f060fec8a2a2d789818f4e15733fa' 
  AND token = 'eWij1p2fbVcKVKtdbdPsPhTYtu2Wozilr+Q+YCXsgOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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