SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c247cb52e626f223ab2c5ba6fd52b5b9c5069c330fcc13ee989e55369cea61' 
  AND token = '3fafadHLjUDCioJ1+AmHVUMTOe8pw4zrT0FBBmkwsiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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