SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd841f043199ff767de2d51e08129c7a3fa251c72eba2e8d83064fd7908a2a7' 
  AND token = 'o831TR+aN9Ka+hDcMwI0qXrecF5vMaOabtLpE+GA/Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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