SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91844ae54ed479ebafd4834762dac273ca9c760df1372a5a80862a0164f48347' 
  AND token = 'T8P/iMNhT4J/72zbhO8zP1dtanIjW5CZeg3lRzVleuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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