SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acfff435aefc972fd7ec9478e05c457bb1613a3e26f42af60520c5a767720d37' 
  AND token = 'yv8jUrQSfI1/xh+MUZtIJu4p1VSAVnCzPdQ7mDKnOYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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