SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f8254a67b87b8dd22d9bca1a358237ed0ebb2a75720c109e58cfbfd79d65994' 
  AND token = 'IYWtBEVVLKI6wI5m+BdH3NN3wfnrSuBk25FNY0UkuCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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