SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68230dd0717f0776859fe102b1490101faffa62b4729ad2820af5de4bd803a68' 
  AND token = 'YI7gX9IH69Ovbw9vnQWyXuQjd61GRfUh97ddYlOmhJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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