SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dfd23ae284b806924bd31067afaa7446418e7f749aaa829d462a277d038d9cc' 
  AND token = 'XWf9ETAIa7ijMwK+yo9Knzjx5G0+/pUUGvu9BS+uq5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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