SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9376aca7749d27e9a6e1d873ebe159470669e1cd7a1beea528853baac3143332' 
  AND token = 'M94JSxUW5+zXfFtaWrs/twPx6BP2ukLlAUhyP16AAEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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