SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fea62b214cf0b1d4748604bdb4fd0ef6c3aec94b677d855f08f390565abd5350' 
  AND token = 'dfczQW9BiuvpDzR+8LBrlYZxvWnzP14Wpnk09LyN2xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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