SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737caeca4496b3972cf24d3231d1462b5b7ea6458b22a729dd0fb1d9987e4945' 
  AND token = 'Q/j0XcZlstPZHTxpkrL6MTxoRMZFEifq7tIDBH9P7TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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