SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a1a0cdc7fa42100bfae4afeae393e5316bb151b96dd33298831130c0a822a77' 
  AND token = 'vQ+TJQYZ8Vi4GQYykhSZCDK4UhLqqch+uGk+fC453PA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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