SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4e46f95e3bb30752b4af9b7f98b18973c74271fe1fd175a673c3612a6c1ba0' 
  AND token = 'mZ9ZPpNVaJGvRpmTDwAJcc5ABTL/c5L04HKEhjsEDTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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