SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '716d99dd28fbc8016ffb39c6ae9f15f83f015e234cfa76a500f339fe805d8a7e' 
  AND token = 'ehKkqpdhnjrx5Uze1Q643xXNgqvnJXUyxG2xPcD+P/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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