SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc28e46c151dbacdd360838eef04340fcce1cde7064784470307224f33cce8b6' 
  AND token = 'GUDkr+Dxk6vYUoRZBzCwvWaati8/nivgS4pszwUiby8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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