SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90b16dd227ab1300501a5b100833dd0a69d6ef3f80048d4f1a6db65698f41b8e' 
  AND token = 'DsDKhT63qrfvWlOBHFpVIJaTtdEYoV/udRQ7ErNfsp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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