SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d2959d278e4e52bcb4d313a78f628627ccc0ed61b849fbf91ed9d17b70a181' 
  AND token = 'rP6dCgtxCgKsvOHQJpJhLJogVdt+GxrZxGL3v8StR5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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