SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1829c316f34e6aa8edfee3cfa6079be4c993aaac4bafc957c5a932f8a020511f' 
  AND token = 'HmqVLLwLFzaNxIwiAQSTxzK/LXqELp5aPbb09EbuHDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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