SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c699d931726b9eb8ac04620a175bfeea3b47ee0ebd387f33020f960cf6319f17' 
  AND token = 'YhLwKXu6X5xcRfEY4u3tzc5ngloplfOvbBOdfGUsOKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}