SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7543152c1c93d9ac65bfd789ca4dbc45e522a7d129f21fd86be0e9a5726e9be3' 
  AND token = '5NNnhx35Ogl6VLsffCGQ+nUusZGGmFmmuZqU+oeqgg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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