SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24aa91cf9c73472e1f1b504842438835fc6a141fe09395dfe8873ccfad11ced6' 
  AND token = 'pqy7l36EaAYBZVVJxectplE/5fsh15XAhFfXg4MHBd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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