SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f43231ee32726b242fae195c58b3529ba8a9c8e766e189bfc31afe8a1f5f8874' 
  AND token = 'rP3PXvWqbuj7ZT/jgqhhMcLAtQcI1nGJGZe/xCfXjdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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