SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24d258a28d9ed5bed7489806cd76c271bc54d4acd63864a210be60f6a3d991db' 
  AND token = '9oSYwG/eyrBnbqNF1JF+FN3vKT5BpjFYxu8RNQI8JQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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