SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a99fa43c16d83699057dd5bc517f43232a7db9140d4df3c8b9992408ede11894' 
  AND token = 'yTYZE6INocaRftbp9yN1N8hPtOqHQ7bDEeRiBMGNzmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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