SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c1f8acf2dbf362202cbb7ee88ffef7347dfcca3e6defebb4cda5a51b63e5e0' 
  AND token = 'e4OdvMNdUGqPOXYiQCFYUowUuVkbzXWAq8ED0vdkAeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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