SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae438798e2f1aa475644ce9f675234692bfd36941625c21cc8eef2896e3458fe' 
  AND token = 'RPnrKTYkppjkUFFXDxQ9f8vTeBLp7PPwSRk4aLxHcNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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