SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5cfa6264d163c14996dd6363c6b2b92a90d74605f363c8206e0ccce4e82750' 
  AND token = 'FL+HK3tAnjAKJTxdWnw47uK+8P7dVlLTfknXs33MEQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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