SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2585f40c493618a4fca7213e7c580b06a3c0d3321d2829f2f42c43d237fd171d' 
  AND token = 'd6dfm/+E8jJcxvYtLhCH0/SDQGgsKsxzJX5jpdVVf48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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