SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead9fbe608f1920cdc586ac2be363e533b1fee6ea0c880c1d39e1594369a3d43' 
  AND token = 'tpeqXuqM4SpnCr/M+LvPsT3ZYD5zOrez7wqEO1O5GOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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