SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd70362d8def031da7b43a00e2b32f819bc5fa155517e95817b96c9f7f6c5a27' 
  AND token = 'kcV2h42NlQUOj6j0Oul42gG3rbdimHU+vzazD+iQZgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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