SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42d44e3322d3c2e0878fd222904ad0ce193ef90893145aaeefe36c5a754bf0dd' 
  AND token = 'X1oeZlEmknvqHacNHPyRnCTbOvp4vEREtUM6nAPfe0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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