SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cc8b49ff020bacf609b93f85b97f15f8eaf21d2375fb857a3795436992ad89c' 
  AND token = 'flSpEUKHHw/oDD+3ZImHkyouldjOysn1ELIgH3Ym3tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}