SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a87afdf6134d743571faba35aefc8f1e281ce3b9b0e195ef11afd87eeccd0dc' 
  AND token = 'UfGMPvD0UrZB1PzrQBpIQOjAcYc48BwGUAZmzZuRNXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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