SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '565794504a1c9c9310e9972035acfddc31a66abcdcf9b219bf5c967bd9099032' 
  AND token = 'NVoIvP3Shd97B9XU2nELxRuMmKXtk6ftvCAdpJLTctI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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