SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c8d9961d2bd64c461fd3eaf2c8ad2029a44079c15cc4669cb87be0466649716' 
  AND token = 'UVh6tlmjpCJtUFIod3Rrb+/l9dGjQMGtZIsbJNyGzSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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