SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '071803177855251b1d51f6bb476914e40701237b9942a40982cfc7cc791850cf' 
  AND token = 'A5H9bYP3WxxpMCN0UnCaksHS9zLLaSFJRvqGjnAEF/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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