SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a6730b94eb673795ecdfe5728575c8e1dc776c0c8f95cec6a376f3f31eb5f4' 
  AND token = 'cHaVURkafBRe32SmrlztoIZYf3TJlTziayKk0HRawfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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