SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7675c6709990c8abb5f8d6b5d4459a8d1e67358303f1a65068ec0f99c4b1c9f' 
  AND token = '/dbmTqpYnuoZPd2zZ5xgBD64ZvgQVwNkqo5VQbf8KQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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