SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c5d3cacf026c0982e4949f6bf635eebcf67f1dd35ffe8a7d8cd9adf8cdc1e4d' 
  AND token = 'T+kukxpvEAYqPKZmjwp0zU7+hJm/I4ULusrbXqhHkvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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