SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f82da6a4b000c9e9c9ffe72e507ec531a8bcf0ed59cf7627e9a3f23d021d55df' 
  AND token = 'UmOfnJys/JXkAsV7jIveh6p88nasUbYUeiy/3HVndvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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